feat: build and publish the publiccode.yml website on GitHub Pages

Author: bfabio

.github/workflows/publish.yml

@@ -0,0 +1,62 @@
+name: publish
+
+on:
+  workflow_dispatch:
+  # Sent by the publish workflow of publiccodeyml/publiccode.yml on
+  # every push to main, a draft branch or a release tag.
+  repository_dispatch:
+    types: [publish]
+  # Fallback in case a dispatch gets lost.
+  schedule:
+    - cron: "23 5 * * *"
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: publish
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      # The toolchain (poly.py, conf.py, templates) always comes from main,
+      # the content of each version from its release tag or draft branch.
+      - uses: actions/checkout@v7
+        with:
+          repository: publiccodeyml/publiccode.yml
+          ref: main
+          fetch-depth: 0
+      - uses: astral-sh/setup-uv@v7
+        with:
+          version: "0.12.5"
+          enable-cache: true
+
+      # Release tags come with the checkout, but sphinx-polyversion only
+      # looks at local branches for the drafts
+      - name: Create the draft branches
+        run: |
+          for ref in $(git for-each-ref --format='%(refname:lstrip=3)' 'refs/remotes/origin/[0-9]*-rc'); do
+            git branch "$ref" "origin/$ref"
+          done
+          git branch --list
+          git tag --list 'v*'
+
+      - run: uv run sphinx-polyversion poly.py build/html -vv
+
+      - uses: actions/upload-pages-artifact@v5
+        with:
+          path: build/html
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - id: deployment
+        uses: actions/deploy-pages@v5

README.md

@@ -0,0 +1,15 @@
+# publiccodeyml.github.io
+
+The website of the [publiccode.yml Standard](https://github.com/publiccodeyml/publiccode.yml),
+served at <https://publiccodeyml.github.io>.
+
+There is nothing to edit here: the content and the Sphinx toolchain live
+in the `publiccode.yml` repository. The
+[publish workflow](.github/workflows/publish.yml) checks it out, builds
+every version line with sphinx-polyversion and deploys the result on
+GitHub Pages.
+
+A build runs on each push to `main`, to a draft branch or to a release
+tag of `publiccode.yml`, which sends a `repository_dispatch` event here.
+A daily scheduled run covers a lost dispatch, and the workflow can also
+be started by hand from the Actions tab.