Update stefanzweifel/git-auto-commit-action action to v6

Author: renovate[bot]

.github/workflows/autoformat-pixeebot-prs.yaml

@@ -27,6 +27,6 @@ jobs:
         run: black .
 
       - name: Commit and push changes
-        uses: stefanzweifel/git-auto-commit-action@v5
+        uses: stefanzweifel/git-auto-commit-action@v6
         with:
           commit_message: ":art: Apply formatting"