Revert "You can use GITHUB_TOKEN already provided by Github Actions (#100)" (#101)

This reverts commit 14c185d.

Author: serras

.github/workflows/deploy.yml

@@ -32,6 +32,6 @@ jobs:
     - name: Deploy microsite
       uses: peaceiris/actions-gh-pages@v2
       env:
-        ACTIONS_DEPLOY_KEY: ${{ secrets.GITHUB_TOKEN }}
+        ACTIONS_DEPLOY_KEY: ${{ secrets.ACTIONS_DEPLOY_KEY }}
         PUBLISH_BRANCH: gh-pages
         PUBLISH_DIR: ./gen-docs