refactor: changed to install [test] dependencies instead of raw pylin…

…t install

.github/workflows/pylint.yml

@@ -17,7 +17,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install pylint
+        pip install -e '.[test]'
     - name: Analysing the code with pylint
       run: |
         pylint mkpdfs_mkdocs