feat: install dev requirements as well

.github/workflows/pylint.yml

@@ -18,8 +18,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt 
-        pip install pylint
-        pip install black
+        pip install -r dev_requirements.txt 
     - name: Analysing the code with pylint
       run: |
         pylint $(git ls-files '*.py')