Fix install command

Author: daneah

.github/workflows/ch07-packaging.yml

@@ -68,7 +68,7 @@ jobs:
           python-version: ${{ matrix.python.version }}
 
       - name: Install tox
-        run: python -m install tox
+        run: python -m pip install tox
 
       - name: Run pytest
         run: tox -e ${{ matrix.python.toxenv }}