Apply suggestions from code review

Author: cclauss

.github/workflows/continuous_integration.yml

@@ -45,7 +45,7 @@ jobs:
         python -m build
     - name: Test with tox
       run: |
-        python -m pip install tox tox-gh-actions setuptools
+        python -m pip install tox tox-gh-actions
         tox
     - name: Publish to Coveralls with GitHub Action
       uses: coverallsapp/github-action@v2

tox.ini

@@ -16,7 +16,6 @@ deps =
     numpy
     pytest>=2.9.2
     pytest-cov>=2.2.1
-    setuptools
 commands = pytest test --cov openhtf --cov-report=term-missing --cov-report=lcov
 # usedevelop causes tox to skip using .tox/dist/openhtf*.zip
 # Instead, it does 'python setup.py develop' which only adds openhtf/ to the