Envoy-data-plane

* upgrade protobufs to envoy version 1.28.0
* upgrade dev dependency betterproto to beta 6
* changed author email

Updated betterproto from b5 to b6

* Upgraded betterproto to 2.0.0b5
* Updated protos to 1.25.0

What's Changed
* Keeping protobufs up to date in the pypi package by cetanu in https://github.com/cetanu/envoy_data_plane/pull/14


**Full Changelog**: https://github.com/cetanu/envoy_data_plane/compare/0.3.0...0.4.0