Regenerate config_pb2.py with `libprotoc 3.21.12`

[nicdumz]

Otherwise Python3 is unhappy with this file:

Traceback (most recent call last):
  File "beangrow/configure.py", line 23, in <module>
    from beangrow.config_pb2 import Config
  File "beangrow/config_pb2.py", line 36, in <module>
    _descriptor.FieldDescriptor(
  File "<venv>/lib/python3.11/site-packages/google/protobuf/descriptor.py", line 561, in __new__
    _message.Message._CheckCalledFromGeneratedFile()
TypeError: Descriptors cannot not be created directly.
If this call came from a _pb2.py file, your generated code is out of date and must be regenerated with protoc >= 3.19.0.
If you cannot immediately regenerate your protos, some other possible workarounds are:
 1. Downgrade the protobuf package to 3.20.x or lower.
 2. Set PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python (but this will use pure-Python parsing and will be much slower).

More information:
https://developers.google.com/protocol-buffers/docs/news/2022-05-06#python-updates