Increment protobuf requirement

[vespakoen]

When trying to use the latest wirepass-mesh-messaging-python version with wirepass-mqtt-library, I got this error:

  from app import wirepas_client
File "/code/app/wirepas_client.py", line 3, in <module>
  from wirepas_mqtt_library import WirepasNetworkInterface
File "/usr/local/lib/python3.11/site-packages/wirepas_mqtt_library/__init__.py", line 1, in <module>
  from .wirepas_network_interface import WirepasNetworkInterface
File "/usr/local/lib/python3.11/site-packages/wirepas_mqtt_library/wirepas_network_interface.py", line 11, in <module>
  import wirepas_mesh_messaging as wmm
File "/usr/local/lib/python3.11/site-packages/wirepas_mesh_messaging/__init__.py", line 22, in <module>
  from .get_configs import GetConfigsRequest, GetConfigsResponse
File "/usr/local/lib/python3.11/site-packages/wirepas_mesh_messaging/get_configs.py", line 10, in <module>
  from .proto import GenericMessage
File "/usr/local/lib/python3.11/site-packages/wirepas_mesh_messaging/proto/__init__.py", line 5, in <module>
  from .error_pb2 import *
File "/usr/local/lib/python3.11/site-packages/wirepas_mesh_messaging/proto/error_pb2.py", line 5, in <module>
  from google.protobuf.internal import builder as _builder

I solved it by incrementing the protobuf version requirement, it looks like error_pb2.py (auto-generated?) depends on builder, which seems to be added in protobuf 3.20.0, see: https://github.com/protocolbuffers/protobuf/releases/tag/v3.20.0, especially the line: *[Breaking change] Protobuf python generated codes are simplified. Descriptors and message classes' definitions are now dynamic created in internal/builder.py.