Include changes from 1.30.1 in release notes

Author: Mark-Simulacrum

RELEASES.md

@@ -74,6 +74,14 @@ Cargo
 [cargo-rename-reference]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml
 [const-reference]: https://doc.rust-lang.org/reference/items/functions.html#const-functions
 
+Version 1.30.1 (2018-11-08)
+===========================
+
+- [Fixed overflow ICE in rustdoc][54199]
+- [Cap Cargo progress bar width at 60 in MSYS terminals][cargo/6122]
+
+[54199]: https://github.com/rust-lang/rust/pull/54199
+[cargo/6122]: https://github.com/rust-lang/cargo/pull/6122
 
 Version 1.30.0 (2018-10-25)
 ==========================