simplify tests workflow

Author: jeffjennings

.github/workflows/tests.yml

@@ -22,13 +22,10 @@ jobs:
     - name: Display Python version
       run: python -c "import sys; print(sys.version)"
 
-    - name: Install test dependencies        
+    - name: Install package and dependencies for tests
       run: |
         pip install setuptools --upgrade
-        pip install .[test]
-
-    - name: Install package
-      run: pip install .    
+        pip install .[test] 
 
     - name: Run unit tests
       run: |