CI: update version string

Co-authored-by: Elliott Sales de Andrade <[email protected]>

Author: tacaswell

.github/workflows/main.yaml

@@ -85,7 +85,7 @@ jobs:
           STEPS_DIFFS_ARTIFACT_UPLOAD_OUTPUTS_ARTIFACT_URL: ${{ steps.diffs-artifact-upload.outputs.artifact-url }}
       - name: Publish cheatsheets and handouts
         if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
-        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4
+        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./docs/_build/html/