Update pylint.yml to install requirements if exists

.github/workflows/pylint.yml

@@ -18,6 +18,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install pylint
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: Analysing the code with pylint
       run: |
         pylint $(git ls-files '*.py')