Protocol Buffers Version 21.2 is Released!

[Theo Rose]

This version includes the following non-breaking changes:

C++

  * ArenaString improvements (fix alignment issue)

PHP

  * API changes for OneOf  (#10102)

You can view the release on [GitHub](https://github.com/protocolbuffers/protobuf/releases/tag/v21.2).

If you experience any issues with the release, please [file a bug](https://github.com/protocolbuffers/protobuf/issues/new/choose) or post on [the Protocol Buffers forum](https://groups.google.com/g/protobuf).