conda-forge: Pin libprotobuf to 3 until all the dependencies support protobuf >= 22 to fix Windows CI

[traversaro]

🦟 Bug fix

Summary

Workaround for https://github.com/gazebosim/gazebo-classic/pull/3330 . protobuf 22/23 brought many changes, so to fully support it we need to solve the following two issues:

• https://github.com/gazebosim/gz-transport/issues/404
• https://github.com/gazebosim/gazebo-classic/pull/3331

Until then, to get the Windows build to work it is easier to just pin libprotobuf to 3 .

Checklist

• [x] Signed all commits for DCO
• [ ] Added tests
• [x] Updated documentation (as needed)
• [x] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if the library has them)
• [x] codecheck passed (See contributing)
• [ ] All tests passed (See test coverage)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[traversaro]

@scpeters I think we should merge this to avoid that all other PRs have a failing Windows build, such as in https://github.com/gazebosim/gazebo-classic/pull/3309 .

[traversaro]

The proper fix is proposed in https://github.com/gazebosim/gazebo-classic/pull/3331, so I think we can close this workaround PR.