Update buf plugin with latest v2 beta

Summary

Buf uses 1.2.5 of betterproto package, which cannot process optional keywords

What is the feature request for?

The core library

The Problem

In our company we have a standard to use buf to generate bindings to proto files.
And we wanted to use betterproto plugin to generate idiomatic python code.
Unfortunately, the only version of the plugin (v1.2.5) doesn't support some "newer" protobuf features, like "optional" keyword.
This was fixed in v.2.0.0b4, but this release is not available in buf.

The Ideal Solution

Can I ask to release latest beta (v.2.0.0b7 as the time of writing) as another version of community plugin?
https://github.com/danielgtaylor/python-betterproto/milestone/4 does not seem to be forthcoming.
Thanks

The Current Solution

Rely on official buf python plugin
https://buf.build/protocolbuffers/python?version=v28.0

plugins/community/danielgtaylor-betterproto のコミュニティプラグイン定義から始め、betterproto のリリースをどのように固定しているかを確認します。プラグインを要求されたベータ版 v2.0.0b7 に更新し、Buf が新しいバージョンを公開することと、オプションの protobuf フィールドが正常に生成されることを確認します。