Update tests.yml (#15)

Author: wdar

.github/workflows/tests.yml

@@ -24,7 +24,8 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install ".[dev]"
+          pip install .
+          pip install coverage flake8
 
       - name: Run tests with coverage
         run: |