use pytest instead of coverage

Author: DomAmato

.github/workflows/testlint.yml

@@ -34,6 +34,6 @@ jobs:
       env:
         COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
       run: |
-        pip install coveralls pytest
-        coverage run --source Hologram -m pytest
+        pip install coveralls pytest-cov
+        pytest --cov=Hologram tests/
         coveralls