Update sonarcloud workflow: install local source packages

Author: shorodilov

.github/workflows/sonarcloud.yml

@@ -23,6 +23,9 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install pytest pytest-cov
+      - name: Install source packages
+        run: |
+          pip install -e .
       - name: Collect coverage
         run: |
           coverage run -m pytest