Make AppImage build workflow manual only (workflow_dispatch)

Author: Shikakiben

.github/workflows/appimage.yml

@@ -4,11 +4,6 @@ concurrency:
   cancel-in-progress: true
 
 on:
-  push:
-    branches:
-      - main
-  #schedule:
-    #- cron: "0 7 1/21 * *" # We default to rebuilding every 21 days, change this to your liking
   workflow_dispatch: {}