Stopping the mixing -> clear separation Forgejo/Github

This action is even less useful in Github than in Forgejo/Gitea so let's stop
wasting time and clearly label with a suffix 'v4.x.y-github' for Github.

.forgejo/workflows/generate-release-zipfile.yml

@@ -1,6 +1,7 @@
 on:
   push:
     branches:
+      - 'v4'
 
 jobs:
   GenerateReleaseZipfile:
@@ -55,6 +56,8 @@ jobs:
           # In case the repository becomes private, we add our GITHUB_TOKEN to the artifact-url.
           MY_AUTHENTICATED_URL="$( echo "${{ steps.uploading.outputs.artifact-url }}" | sed "s#^\(https\?://\)#\1$GITHUB_TOKEN\@#" )"
           wget -O "$DOWNLOAD_FILE" "$MY_AUTHENTICATED_URL"
+
+          # unzip and check
           unzip "$DOWNLOAD_FILE"
           sha256sum -c "$SHASUM_FILE"
 

.github/workflows/generate-release-zipfile.yml

@@ -1,6 +1,7 @@
 on:
   push:
     branches:
+      - 'v4-github'
 
 jobs:
   GenerateReleaseZipfile: