Add checkout step to GitHub Actions workflow

Debugging workflow

Author: dsmits

.github/workflows/main.yml

@@ -6,5 +6,10 @@ jobs:
     name: push new content to gh-pages
     runs-on: ubuntu-22.04
     steps:
+      - name: Checkout main
+        uses: actions/checkout@v2
       - name: deploy
         uses: mhausenblas/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+