Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -3,11 +3,11 @@
 ## Style
 We follow PEP8 with the exception of maximum line length set to 120. We
 use `numpy` style docstrings with the exception of ommitting argument
-types in the docstrings in favour of type hint in function and class
+types in the docstrings in favour of type hints in function and class
 signatures. We use `mypy` to typecheck code with exceptions for
 libraries with missing stubs specified in `setup.cfg`.
 
 ## Pull requests
-Before a PR is accepted, CircleCI builds must pass. We use `flake8` for
+Before a PR is accepted, TravisCI builds must pass. We use `flake8` for
 linting (with exceptions to PEP8 described in `setup.cfg` and `pytest`
-for testing. We use `sphinx` for building documentation.
+for testing. We use `sphinx` for building documentation.