ci: auto-build gh-pages branch

Author: supakeen

.github/workflows/deploy.yml

@@ -0,0 +1,39 @@
+name: Deploy
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write  # To push a branch 
+      pull-requests: write  # To create a PR from that branch
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+        submodules: recursive
+    - name: Install pelican
+      run: |
+        python3 -m venv venv
+        ./venv/bin/pip install -U pip
+        ./venv/bin/pip install pelican
+    - name: Deploy GitHub Pages
+      run: |
+        # This assumes your book is in the root of your repository.
+        # Just add a `cd` here if you need to change to another directory.
+        ./venv/bin/pelican
+        git worktree add gh-pages
+        git config user.name "Deploy from CI"
+        git config user.email ""
+        cd gh-pages
+        # Delete the ref to avoid keeping history.
+        git update-ref -d refs/heads/gh-pages
+        rm -rf *
+        mv ../output/* .
+        echo 'bpython-interpreter.org' > CNAME
+        git add .
+        git commit -m "Deploy $GITHUB_SHA to gh-pages"
+        git push --force --set-upstream origin gh-pages