Replace the Pull Request automation with a Hugo one

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/workflows/pr.yml

@@ -0,0 +1,26 @@
+name: Hugo
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: configure Hugo
+      run: |
+        set -x &&
+        echo "HUGO_VERSION=$(sed -n 's/^ *hugo_version: *//p' <hugo.yml)" >>$GITHUB_ENV
+    - name: install Hugo ${{ env.HUGO_VERSION }}
+      run: |
+        set -x &&
+        curl -Lo /tmp/hugo.deb https://github.com/gohugoio/hugo/releases/download/v$HUGO_VERSION/hugo_extended_${HUGO_VERSION}_linux-amd64.deb &&
+        sudo dpkg -i /tmp/hugo.deb
+    - name: run Hugo to build the pages
+      run: hugo
+    - name: build tar archive
+      run: cd public && tar czvf ../pages.tar.gz *
+    - name: Upload build artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: pages
+        path: pages.tar.gz