Test coverage doesn't seem to work on pypy3.

.gitlab-ci.yml

@@ -57,6 +57,7 @@ test:pypy-2:
     - python setup.py test
     - py.test --cov=chkcrontab_lib tests
 
+# TODO(lyda): Fix test coverage here.
 test:pypy-3:
   image: pypy:3-slim
   type: test
@@ -64,4 +65,3 @@ test:pypy-3:
     - pip install pytest-cov
     - python setup.py install
     - python setup.py test
-    - py.test --cov=chkcrontab_lib tests