Add platform definitions for Ubuntu 22.04 and 24.04 for Arm64 (#2410)

As per
https://github.com/bazelbuild/bazel-central-registry/pull/6645#issuecomment-3580746528.

I used `python3` as the Python version for consistency with the x86-64
entries. The 20.04-arm64 entry says `python3.8`.
1 file changed