Update push_master.yml

.github/workflows/push_master.yml

@@ -26,6 +26,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
+        pip install prometheus_client
         pip install pylint
     - name: Analysing the code with pylint
       run: pylint --exit-zero $(git ls-files '*.py')