protobuf issue with keepkey_agent 0.9.0

[chenrui333]

While trying to upgrade keepkey_agent 0.9.0 to build against py3.12 (along with some dependency updates), I ran into some runtime failure as below:

2023-10-17 16:52:35,198 WARNING      DISPLAY not defined                                                                                  [ui.py:92]
Traceback (most recent call last):
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/bin/keepkey-agent\", line 8, in <module>
    sys.exit(ssh_agent())
             ^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/bin/keepkey_agent.py\", line 5, in <lambda>
    ssh_agent = lambda: libagent.ssh.main(keepkey.KeepKey)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/ssh/__init__.py\", line 173, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/ssh/__init__.py\", line 308, in main
    for pk in conn.public_keys():
              ^^^^^^^^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/ssh/__init__.py\", line 209, in public_keys
    self.public_keys_cache = conn.export_public_keys(self.identities)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/ssh/client.py\", line 24, in export_public_keys
    with self.device:
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/device/interface.py\", line 126, in __enter__
    self.conn = self.connect()
                ^^^^^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/device/trezor.py\", line 50, in connect
    transport = self._defs.find_device()
                ^^^^^^^^^^
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/device/keepkey.py\", line 30, in _defs
    from . import keepkey_defs
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/libagent/device/keepkey_defs.py\", line 5, in <module>
    from keepkeylib.client import CallException
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/keepkeylib/client.py\", line 37, in <module>
    from . import mapping
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/keepkeylib/mapping.py\", line 1, in <module>
    from . import messages_pb2 as proto
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/keepkeylib/messages_pb2.py\", line 17, in <module>
    from . import types_pb2 as types__pb2
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/keepkeylib/types_pb2.py\", line 18, in <module>
    from . import exchange_pb2 as exchange__pb2
  File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/keepkeylib/exchange_pb2.py\", line 32, in <module>
    _descriptor.EnumValueDescriptor(
    File \"/home/linuxbrew/.linuxbrew/Cellar/keepkey-agent/0.9.0_7/libexec/lib/python3.12/site-packages/google/protobuf/descriptor.py\", line 796, 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

relates to Homebrew/homebrew-core#151437

For now i am gonna downgrade protobuf dependency to 3.20.3