separate push step and clean lines

Author: mmenanno

.github/workflows/dependabot-rbi-updater.yml

@@ -33,9 +33,12 @@ jobs:
       -
         name: Commit RBIs
         run: |
-          git checkout ${{ github.head_ref }}
           git config --local user.name "Dependabot RBI Updater"
           git config --local user.email action@github.com
-          git add sorbet/*
-          git diff-index --quiet HEAD || git commit -m "[dependabot skip] Update RBIs"
-          git push
+          git commit -a -m "[dependabot skip] Update RBIs"
+      -
+        name: Push changes
+        uses: ad-m/github-push-action@v0.8.0
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          branch: ${{ github.head_ref }}