Use coverage.ini in Travis

Author: brettcannon

.travis.yml

@@ -14,7 +14,7 @@ install:
   - python3 -m pip install --upgrade mypy coverage
 
 script:
-  - python3 -m coverage run -m unittest discover
+  - python3 -m coverage run --rcfile=coverage.ini -m unittest discover
   - mypy --ignore-missing-imports importlib_resources
 
 after_success: