protobuf 4.21 support

Currently, we are locked into 3.x with `~=3.13`.

If I forcibly install 4.21, I get this:

```
E TypeError: Descriptors cannot not be created directly.
E If this call came from a _pb2.py file, your generated code is out of date and must b
e regenerated with protoc >= 3.19.0.
E If you cannot immediately regenerate your protos, some other possible workarounds ar
e:
E 1. Downgrade the protobuf package to 3.20.x or lower.
E 2. Set PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python (but this will use pure-Python
parsing and will be much slower).
E
E More information: https://developers.google.com/protocol-buffers/docs/news/2022-05-0
6#python-updates
```

Would it be possible to regenerate with a newer protoc and allow for protobuf v4 to be used?

Thank you!