Issue danielfrg#135 make test workflow lighter: only install necessary deps

Author: soxofaan

.github/workflows/test.yml

@@ -36,7 +36,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip --version
-        pip install -U -r requirements-dev.txt
+        pip install -U pytest pytest-cov
         pip freeze
 
     - name: Build package