Rework auto-merge for Steward's PRs. (#337)

Signed-off-by: Ignacio Lucero <ignacio.lucero@moia.io>

Author: houcros

.github/workflows/automatic-merge.yaml

@@ -15,10 +15,14 @@ jobs:
         with:
           app_id: 162267
           private_key: ${{ secrets.SCALA_STEWARD_APP_PRIVATE_KEY }}
-
       - name: Launch Scala Steward
         uses: scala-steward-org/scala-steward-action@v2
         with:
           github-token: ${{ steps.generate-token.outputs.token }}
           author-name: scala-steward
           author-email: 162267+scala-steward-for-moia[bot]@users.noreply.github.com
+      - name: Enable auto-merge
+        run: gh pr merge --auto --squash "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}