fix Pylint E0401 (import-error)

install requirements.txt before linting

.github/workflows/pylint.yml

@@ -17,6 +17,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
+        pip install -r requirements.txt
         pip install pylint
     - name: Analysing the code with pylint
       run: |