Release v0.22.0

[johnbartholomew]

Release process has started.

• Release Candidate 1 published at https://github.com/google/jsonnet/releases/tag/v0.22.0-rc1 and https://pypi.org/project/jsonnet/0.22.0rc1/

I'll give it a couple of weeks and then hopefully publish v0.22.0.

[johnbartholomew]

Bazel registry update: bazelbuild/bazel-central-registry#7928

[He-Pin]

Wow, it's comming~