Updating

鉴于个人原因，这之后的部分译者并不打算翻译。

This guide is intended to facilitate upgrading to the next minor or major version of Rand. Note that updating to the next patch version (e.g. 0.5.1 to 0.5.2) should never require code changes.

This guide gives a few more details than the changelog, in particular giving guidance on how to use new features and migrate away from old ones.

延伸阅读： History of the Rand crate