docs: document and finalize Gin v1.12.0 release
docs: document and finalize Gin v1.12.0 release: a task in repo2rlenv-pr-diff (Harbor dataset). Title: docs: document and finalize Gin v1.12.0 release
The task
**Title:** docs: document and finalize Gin v1.12.0 release
Part of FineEnvs/repo2rlenv-pr-diff.