Revert "Disable automatic tarball build"

This reverts commit aa87742be0.

.forgejo/workflows/generate-tarball.yml

@@ -10,6 +10,14 @@ on:
         required: true
         type: string
 
+  push:
+    tags:
+      - 'v3*'
+    tags-ignore:
+      - '*-nightly*'
+      - '*-beta*'
+      - '*-alpha*'
+
 jobs:
   build-tarball:
     name: Build tarball