maint: Support protobuf Python library v5

[poodlewars]

Is your feature request related to a problem? Please describe.
Protobuf has released version 5 but we only support version 3 and 4. PR #1421 has constrained protobuf version for now.

We should relax this constraint that we are imposing on user's envs.

Our proto handling is quite complex - we compile Python proto stubs suitable for both proto 3 and proto 4 and choose which a user will "see" at runtime based on their installed proto version.

The solution should consider both wheels and Conda builds.

[jjerphan]

Currently ArcticDB's conda packages are built for:

• protobuf 4 on main since there are less constraints and to follow the ecosystem's releases
• protobuf 3 for all the other branches to do environment contraints, see the specification for libevent-2.1.10's for instance

protobuf 5 has not yet been published on conda-forge. conda-forge/libprotobuf-feedstock#213 is the first PR to start this work.

We might need to define a build variant for protobuf 3, 4, and 5 once this last version is supported.

[jjerphan]

Related grpc/grpc#36142.

[rhoens]

Hi, any movement on this? Just curious if there's a timeline

[jjerphan]

Likely addressable for conda-forge's builds once conda-forge/protobuf-feedstock#216 is completed.