youtube-music: fix WMClass (#3324) (#3327)

(cherry picked from commit 3bdb0e8da3)

Co-authored-by: Cappy Ishihara <cappy@cappuchino.xyz>

anda/apps/youtube-music/youtube-music.desktop

@@ -5,6 +5,6 @@ TryExec=/usr/bin/youtube-music
 Icon=youtube-music
 Terminal=false
 Type=Application
-StartupWMClass=YouTube Music
+StartupWMClass=com.github.th_ch.youtube_music
 Comment=YouTube Music Desktop App - including custom plugins
 Categories=AudioVideo;

anda/apps/youtube-music/youtube-music.spec

@@ -13,7 +13,7 @@
 
 Name:           youtube-music
 Version:        3.7.2
-Release:        2%?dist
+Release:        3%?dist
 Summary:        YouTube Music Desktop App bundled with custom plugins (and built-in ad blocker / downloader)
 Source1:        youtube-music.desktop
 License:        MIT