Support for protobuf >= 22 by using find_package(Protobuf CONFIG)

[traversaro]

🎉 New feature

Fix compatibility with protobuf >= 22, similar to gazebosim/gz-msgs#346 and other PRs linked there.

Summary

To minimize the risk of regression when protobuf < 22 is used, the protobuf version is obtained via pkg-config. If protobuf >= 22 is detected, then find_package(Protobuf CONFIG REQUIRED) is used and protobuf::libprotobuf and protobuf::libprotobuf are linked to make sure that the dependency with abseil is correctly handled.

Test it

See conda-forge CI that now passes. Probably this PR can also be tested on homebrew that recently upgraded protobuf to 23.2, see Homebrew/homebrew-core#132957 .

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• 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]

This patch worked fine in conda-forge/gazebo-feedstock#178 .

[talregev]

@traversaro, it seem you fix the windows issue. Are you going to merge it?

[scpeters]

I wanted to rerun CI now that the citadel bottles of gazebo11 dependencies are fixed, and I noticed a minor whitespace issue, so I pushed c4674ee to rerun CI

[scpeters]

CI looks good