Add a deploy docs step to CI

.github/workflows/ci.yml

@@ -58,6 +58,18 @@ jobs:
         with:
           github-token: ${{ secrets.github_token }}
           parallel-finished: true
+  deploy-docs:
+    name: Deploy docs
+    runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
+    steps:
+      - name: Checkout main
+        uses: actions/checkout@v2
+
+      - name: Deploy docs
+        uses: mhausenblas/mkdocs-deploy-gh-pages@master
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 #  deploy:
 #    needs: test
 #    runs-on: ubuntu-latest