Log Message:
{py-,}protobuf: update to [34].21.5

2022-08-09 version 21.5 (C++/Java/Python/PHP/Objective-C/C#/Ruby)

  PHP
  * Added getContainingOneof and getRealContainingOneof to descriptor.
  * fix PHP readonly legacy files for nested messages

  Python
  * Fixed comparison of maps in Python.