attempt to work around issue with pip

.github/workflows/build.yaml

@@ -20,10 +20,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install packages
         run:
-          python -m pip install --upgrade pip
-          pip install tox
-          pip install coveralls
-          pip install .
+          python -m pip install --upgrade pip tox coveralls .
       - name: Run tests
         run: tox
       - name: Report test coverage