fix: install package in CI before running tests

Author: Vladyslav Lyshenko

.github/workflows/tests.yml

@@ -25,7 +25,7 @@ jobs:
           python-version: ${{ matrix.python }}
 
       - name: Install dependencies
-        run: pip install pytest
+        run: pip install -e ".[dev]"
 
       - name: Run tests
         run: pytest tests/ -v