Fix broken Contributing Guide link in README (#528)

docs: fix contributing link

Author: rovazh

README.md

@@ -1086,8 +1086,7 @@ build it yourself, you'll need these prerequisites:
 ## Contributing
 
 We're happy to accept contributions and PRs! Please see the [contribution
-guide](/okta/okta-sdk-golang/blob/master/CONTRIBUTING.md) to understand how to
-structure a contribution.
+guide](CONTRIBUTING.md) to understand how to structure a contribution.
 
 [devforum]: https://devforum.okta.com/
 [sdkapiref]: https://godoc.org/github.com/okta/okta-sdk-golang/v4/okta