update contributing link for PRs

CONTRIBUTING.rst

@@ -96,6 +96,6 @@ Before you submit a pull request, check that it meets these guidelines:
    your new functionality into a function with a docstring, and add the
    feature to the list in README.rst.
 3. The pull request should work for Python 3.7+. Check 
-   https://travis-ci.org/tsroten/zhon/pull_requests
+   https://github.com/tsroten/zhon/actions?query=event%3Apull_request
    and make sure that the tests pass for all supported Python versions.
 4. If you want to receive credit, add your name to `AUTHORS.rst`.