actions: add duplicate detection

.gitea/workflows/build-and-push.yaml

@@ -75,8 +75,13 @@ jobs:
           git config --local user.signingkey ~/.ssh/id_ed25519
           git config --local gpg.format ssh
           git config --local commit.gpgsign true
-          git commit -a -m "yt-dlp-bot: deploy update to ${{ needs.build-and-push.outputs.sha_short }}"
           
+          if [ -n "$(git status --porcelain)" ]; then
+            git commit -a -m "yt-dlp-bot: deploy update to ${{ needs.build-and-push.outputs.sha_short }}"
+          else
+            echo "No changes to commit, skipping..."
+          fi
+          exit 0
       - name: Push changes
         uses: ad-m/github-push-action@v1.0.0
         with: