updated github action workflow to use pip install .[dev] instead of requirements

Author: jspaaks

.github/workflows/tests.yml

@@ -15,8 +15,8 @@ jobs:
         python-version: '3.x'
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        python3 -m pip install --upgrade pip setuptools
+        pip install .[dev]
     - name: Run tests
       run: |
         pytest