For example, 1.0.0 -> 1.0.1,
-version = "1.0.0"
+version = "1.0.1"E.g., https://github.com/rust-lang/rustfmt/commit/5274b49caa1a7db6ac10c76bf1a3d5710ccef569
cargo publish
Note that if you are updating rustc-ap-* crates, then you need to update every submodules in the rust-lang/rust repository that depend on the crates to use the same version of those.
As of 2019/05, there are two such crates: rls and racer (racer depends on rustc-ap-syntax and rls depends on racer, and rls is one of submodules of the rust-lang/rust repository).