CI: Fix building documentation

.github/workflows/gating.yaml

@@ -10,22 +10,19 @@ jobs:
   tests:
     name: Unit tests
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v3
 
-      - name: Set up Python ${{ matrix.python-version }}
+      - name: Set up Python
         uses: actions/setup-python@v3
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: "3.9"
 
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install poetry tox tox-gh-actions
+          pip install poetry tox
 
       - name: Test with tox
         run: tox -e py
@@ -41,6 +38,14 @@ jobs:
           pip3 install --upgrade coveralls==3.2.0
           coveralls --service=github
 
+      - name: Set up Python for documentation build
+        uses: actions/setup-python@v3
+        with:
+          python-version: "3.8"
+
+      - name: Test building documentation with tox
+        run: tox -e docs
+
   coveralls-finish:
     name: Finish coveralls-python
     needs: tests
@@ -62,7 +67,6 @@ jobs:
         tox_env:
           - bandit
           - lint
-          - docs
 
     runs-on: ubuntu-latest
 
@@ -109,17 +113,14 @@ jobs:
       IMAGE_NAME: greenwave
       REGISTRY: quay.io/factory2
       GH_REGISTRY: ghcr.io/${{ github.actor }}
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v3
 
-      - name: Set up Python ${{ matrix.python-version }}
+      - name: Set up Python
         uses: actions/setup-python@v3
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: "3.9"
 
       - name: Install dependencies
         run: |