infra: Install only tox for python-package workflow (#165)

Author: speller26

.github/workflows/python-package.yml

@@ -25,8 +25,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        pip install --upgrade pip
-        pip install -e .[test]
+        pip install tox
     - name: Run unit tests
       run: |
         tox -e unit-tests