fix load of venv .bemol

Author: wagnerjpinto

.github/workflows/python-test-pip.yml

@@ -26,6 +26,7 @@ jobs:
     
     - name: Lint with flake8
       run: |
+        source .bemol/bin/activate
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide