fix(docs): fix outdated contribution section (#11683)

Fixes #11634.

Author: suztomo

README.md

@@ -664,11 +664,7 @@ runtime. However, Datastore, Storage, and Bigquery should work.
 
 ## Contributing
 
-Contributions to this library are always welcome and highly encouraged.
-
-See `google-cloud`'s [CONTRIBUTING] documentation and the [shared documentation](https://github.com/googleapis/google-cloud-common/blob/main/contributing/readme.md#how-to-contribute-to-gcloud) for more information on how to get started.
-
-Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms. See [Code of Conduct][code-of-conduct] for more information.
+See [CONTRIBUTING.md](CONTRIBUTING.md).
 
 ## License
 
@@ -686,4 +682,4 @@ Apache 2.0 - See [LICENSE] for more information.
 [TESTING]: https://github.com/googleapis/google-cloud-java/blob/main/TESTING.md
 [cloud-platform]: https://cloud.google.com/
 [cloud-platform-docs]: https://cloud.google.com/docs/
-[client-lib-docs]: https://cloud.google.com/java/docs/reference
+[client-lib-docs]: https://cloud.google.com/java/docs/reference