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Closes #18 (closed)

Closes #19 (closed)

Changes

1. Use unified greeting message
2. Add description info for label config
3. Clarify sub-labels and type-labels reminder message
4. Change label ~QA to ~type::qa
5. Add sub-labels for ~type::qa

Staing Verify

https://staging.jihulab.com/gitlab-cn/gitlab/-/merge_requests/10