refactor: source venv

Author: JuroOravec

.github/workflows/tests.yml

@@ -48,7 +48,11 @@ jobs:
         python -m pip install -r requirements-ci.txt
 
     - name: Build Python package
-      run: maturin develop
+      run: |
+        source .venv/bin/activate
+        maturin develop
 
     - name: Run Python tests
-      run: pytest
+      run: |
+        source .venv/bin/activate
+        pytest