add github action for version releases to Sonatype

[shijiesheng]

What changed?

• added a github action release.yaml on push-tag and manual triggers (For safety, currently it's only auto-push-to-staging-and-close mode and requires manual release on sonatype)
• added gralde nexus plugin
• bump version to 3.12.7-SNAPSHOT

Plan:
after it's tested against some version upgrade, we can switch mode to auto-release

Why?

Releasing requires PGP key access + sonatype access. These overheads slow down the release process

How did you test it?

Tested nexus plugin locally on staging repository
Test with act locally

act -j release --secret-file dummy
...
[Release to Maven Central/release]   ✅  Success - Main Publish to Sonatype OSSRH (Maven Central) [2m0.223553458s]
[Release to Maven Central/release] ⭐ Run Complete job
[Release to Maven Central/release] Cleaning up container for job release
[Release to Maven Central/release]   ✅  Success - Complete job
[Release to Maven Central/release] 🏁  Job succeeded

Potential risks

Release notes

Documentation Changes

[shijiesheng]

integration test failed due to cadence-workflow/cadence#6881

[3vilhamster]

It is nice to have automation here as we have on Go client.