Add build docs workflow to github

Until the the readthedocs hook is fixed we use this workflow to verify
the doc.

.github/workflows/build-docs.yml

@@ -0,0 +1,27 @@
+name: Build docs 
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    # Check all PR
+
+jobs:
+  tests:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-22.04
+            python-version: "3.11"
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+    - run: pip install tox
+
+    - name: run sphinx docs build
+      run: tox -e docs