Revert "ci: correctly install from source in ci"

This reverts commit 52474a4.

.github/workflows/python-package.yml

@@ -30,11 +30,11 @@ jobs:
     - name: Install from source
       run: |
         python -m pip install --upgrade pip
-        pip install setuptools
+        pip install pytest
+        pip install -r requirements.txt -r tests/requirements.txt
         python setup.py install
     - name: Test with pytest
       run: |
-        pip install -r tests/requirements.txt
         pytest -vvv
 
   linter: