Update license for Steve Daulton's bundled Nyquist plug-ins

Cherry-picked from upstream Audacity project as seen here:

df091bbde3

Signed-off-by: Panagiotis Vasilopoulos <hello@alwayslivid.com>

plug-ins/StudioFadeOut.ny

@@ -5,8 +5,8 @@ $name (_ "Studio Fade Out")
 $manpage "Fades#studio_fadeout"
 $action (_ "Applying Fade...")
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 ;; StudioFadeOut.ny by Steve Daulton December 2012.
 ;;
@@ -14,7 +14,7 @@ $copyright (_ "Released under terms of the GNU General Public License version 2"
 ;; Applies a sinusoidal fade out with a progressive low-pass
 ;; filter from full spectrum at start to 100 Hz at end.
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/adjustable-fade.ny

@@ -8,10 +8,10 @@ $manpage "Adjustable_Fade"
 $debugbutton false
 $action (_ "Applying Fade...")
 $author (_ "Steve Daulton")
-$release 2.3.1
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/crossfadeclips.ny

@@ -7,13 +7,13 @@ $name (_ "Crossfade Clips")
 $manpage "Crossfade_Clips"
 $action (_ "Crossfading...")
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2") 
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later") 
 
 
 ;; crossfadeclips.ny by Steve Daulton Dec 2014.
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/crossfadetracks.ny

@@ -7,12 +7,12 @@ $debugbutton disabled
 $action (_ "Crossfading...")
 $preview selection
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 ;; crossfadetracks.ny by Steve Daulton Nov 2014 / Sep 2015
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/eq-xml-to-txt-converter.ny

@@ -6,11 +6,11 @@ $manpage "EQ_XML_to_TXT_Converter"
 $debugbutton false
 $preview disabled
 $author (_ "Steve Daulton")
-$release 3.0.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/label-sounds.ny

@@ -8,10 +8,10 @@ $debugbutton false
 ;; As this is a new plug-in (Jan2021), display errors if they occur.
 $debugflags trace
 $author (_ "Steve Daulton")
-$release 3.0.2
-$copyright (_ "Released under terms of the GNU General Public License version 2 or later.")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
-;; Released under terms of the GNU General Public License version 2 or later:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/limiter.ny

@@ -7,12 +7,12 @@ $debugbutton false
 $action (_ "Limiting...")
 $preview enabled
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 ;; limiter.ny by Steve Daulton November 2011, updated May 2015.
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/noisegate.ny

@@ -6,9 +6,10 @@ $manpage "Noise_Gate"
 $debugbutton false
 $preview enabled
 $author (_ "Steve Daulton")
-$release 3.0.1
-$copyright (_ "Released under terms of the GNU General Public License version 2 or later.")
-;; Released under terms of the GNU General Public License version 2 or later:
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
+
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html .
 
 $control mode (_ "Select Function") choice (("Gate" (_ "Gate"))

plug-ins/sample-data-export.ny

@@ -6,8 +6,8 @@ $manpage "Sample_Data_Export"
 $debugbutton false
 $action (_ "Analyzing...")
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 
 $control number (_ "Limit output to first") int-text (_ "samples") 100 1 1000000
@@ -35,7 +35,7 @@ $control messages (_ "Show messages") choice ((_ "Yes")
 
 
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/sample-data-import.ny

@@ -5,8 +5,8 @@ $name (_ "Sample Data Import")
 $manpage "Sample_Data_Import"
 $action (_ "Reading and rendering samples...")
 $author (_ "Steve Daulton")
-$release 2.3.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
 $control filename (_ "Select file") file "" "*default*/sample-data.txt" (((_ "Text file") (txt TXT))
                         ((_ "All files") (""))) "open,exists"
@@ -14,7 +14,7 @@ $control bad-data (_ "Invalid data handling") choice (("ThrowError" (_ "Throw Er
                                                       ("ReadAsZero" (_ "Read as Zero"))) 0
 
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins:

plug-ins/spectral-delete.ny

@@ -4,10 +4,10 @@ $type process spectral
 $name (_ "Spectral Delete")
 $manpage "Spectral_Delete"
 $author (_ "Steve Daulton")
-$release 2.4.0
-$copyright (_ "Released under terms of the GNU General Public License version 2")
+$release 3.0.4
+$copyright (_ "GNU General Public License v2.0 or later")
 
-;; Released under terms of the GNU General Public License version 2:
+;; Released under terms of the GNU General Public License v2.0 or later:
 ;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 ;;
 ;; For information about writing and modifying Nyquist plug-ins: