Cargo.toml: Update to 1.21.1
[package]
name = "rustup"
-version = "1.21.0"
+version = "1.21.1"
authors = [ "Daniel Silverstone <dsilvers@digital-scurf.org>", "Diggory Blake <diggsey@googlemail.com>" ]
build = "build.rs"
documentation = "https://rust-lang.github.io/rustup.rs/rustup/index.html"
