Try building docs on GH actions

Author: dstansby

.github/workflows/docs.yml

@@ -0,0 +1,35 @@
+name: Build docs
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build-and-upload:
+    name: Build & Upload Artifact
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-python@v3
+        with:
+          python-version: "3.10"
+
+      - uses: tlambert03/setup-qt-libs@v1
+
+      - name: Install Dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install ".[docs]"
+      - name: Build Docs
+        uses: aganders3/headless-gui@v1
+        with:
+          run: make html
+          working-directory: ./docs
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: docs
+          path: docs/_build