[Feature Request] Update dependency constraint for protobuf to protobuf>=3.20

[cristiangreco94]

Is your feature request related to a problem? Please describe.

Currently, the dependency specification for protobuf is pinned as protobuf>=3.20,<6. This upper bound prevents usage of the latest protobuf versions (6.x and above), which may block compatibility with other libraries or tools that already depend on newer releases.
Protobuf 5x will reach End of Support in Q1 2026 so it's better to upgrade asap https://protobuf.dev/support/version-support/#python

Describe the solution you'd like

Update the dependency constraint to allow any version of protobuf starting from 3.20 without restricting the upper bound, e.g.:

protobuf>=3.20

This will provide flexibility to use the latest protobuf releases while maintaining compatibility with versions from 3.20 onwards.

Additional context

Removing the <6 upper bound will help ensure this project stays compatible with evolving protobuf releases and reduces dependency conflicts in downstream projects.
https://protobuf.dev/support/version-support/#python Protobuf 5.x will reach End of Support in Q1 2026.

[cretz]

There is a PR in the works to support 6.x at #1082