docs: Update RELEASE.md with the latest release information

Author: raytung

RELEASE.md

@@ -1,9 +1,4 @@
 # Release
 
-## Instructions
-To release the gem to Github package manager and Ruby Gems,
-
-1. Update `lib/fluent/plugin/version.rb`
-2. Create a pull request and merge it into `main`
-3. Manually creating a release on Github with a tag indicating the new version number e.g. `vMAJOR.MINOR.PATCH`
-4. GitHub Actions will automatically run and publish to RubyGems and GitHub repository
+This repository follow conventional commit and semantic versioning, and the release to RubyGems.org and GitHub Ruby
+ Repository is managed by [release-please](https://github.com/google-github-actions/release-please-action).