Set PYTHONPATH in CI/CD pipeline to include src directory

.github/workflows/ci-cd.yml

@@ -26,6 +26,10 @@ jobs:
         python -m pip install --upgrade pip
         pip install -r requirements.txt
 
+    - name: Set PYTHONPATH
+      run: |
+        echo "PYTHONPATH=$PYTHONPATH:${{ github.workspace }}/src" >> $GITHUB_ENV
+
     - name: Run tests
       run: |
         pytest