pin protobuf version in requirements_short.txt

[puzzlemoondev]

protobuf is resolved to 4.x.x without version specified in requirements. This leads to:

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If this call came from a _pb2.py file, your generated code is out of date and must be regenerated with protoc 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).

Pinning to 3.20.x resolves this issue. Reference: https://stackoverflow.com/questions/72441758/typeerror-descriptors-cannot-not-be-created-directly