 yaml-test-suite submodule has broken branch

`yaml-test-suite` submodule links to [053b73a](https://github.com/yaml/yaml-test-suite/tree/053b73a9c12c0cd76da797fdc2ffbd4bb5264c12), which is a commit that "does not belong to any branch on this repository, and may belong to a fork outside of the repository". It causes `git upload-pack: not our ref 053b73a9c12c0cd76da797fdc2ffbd4bb5264c12`

 