Documentation dependencies are required

Author: Guts

.github/workflows/lint-and-tests.yml

@@ -32,12 +32,14 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
           cache: "pip"
+          cache-dependency-path: "requirements/*.txt"
 
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install -r requirements.txt
-          python -m pip install -r requirements/development.txt
+          python -m pip install --upgrade -r requirements.txt
+          python -m pip install --upgrade -r requirements/development.txt
+          python -m pip install --upgrade -r requirements/documentation.txt
 
       - name: Lint with flake8
         run: |