Test docs build.

.github/workflows/build_docs.yml

@@ -1,29 +1,39 @@
 name: Build docs
+
 on:
   push:
     branches:
-      - master
       - main
+      -
 permissions:
   contents: write
+
 jobs:
-  deploy:
-    runs-on: ubuntu-latest
+  build:
+    strategy:
+      matrix:
+        python-version: [ 3.11 ]
+        os: [ ubuntu-latest ]
+    runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
-      - name: Configure Git Credentials
-        run: |
-          git config user.name github-actions[bot]
-          git config user.email 41898282+github-actions[bot]@users.noreply.github.com
-      - uses: actions/setup-python@v5
-        with:
-          python-version: 3.x
-      - run: echo "cache_id=$(date --utc '+%V')" >> $GITHUB_ENV
-      - uses: actions/cache@v4
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
         with:
-          key: mkdocs-material-${{ env.cache_id }}
-          path: .cache
-          restore-keys: |
-            mkdocs-material-
-      - run: pip install mkdocs-material
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install .
+          python -m pip install -r docs/requirements.txt
+
+      - name: Build docs
+        run: |
+          mkdocs build
+          mkdocs build  # twice, see https://github.com/patrick-kidger/pytkdocs_tweaks
+
+      - name: Deploy docs
       - run: mkdocs gh-deploy --force