Bump protobuf to 29.0

[jin]

No description provided.

[shs96c]

We also need to update the version in repositories.bzl

[daniel-b2c2]

Please don't merge this, there is so much dependency cruft with this upgrade that needs explaining on their side, Mockito, Picolocli, OSGi tooling (not OSGi compatibility itself). Do a bazel REPIN and see the following:

DEBUG: /private/var/tmp/_bazel_dan/4062fc18797f0c796822bf92f1458040/external/rules_jvm_external~/private/rules/coursier.bzl:752:18: Found duplicate artifact versions
    com.google.guava:guava has multiple versions 33.3.1-jre, 32.0.1-jre
    org.mockito:mockito-core has multiple versions 5.14.2, 4.3.1
    info.picocli:picocli has multiple versions 4.7.6, 4.6.3

so many other libraries regressed to old versions

I'm not 100% certain but this: biz.aQute.bnd:biz.aQute.bnd.util is osgi buildtime cruft that's made it's way onto the runtime dependency list. Stuff that you use to create osgi dependencies but itself isn't required on the classpath, I could be wrong.

For sure: what on earth is mockito-core doing on a prod classpath.

Polite grumble opened here: protocolbuffers/protobuf#19451