Merge pull request #62 from rubberduck203/coc

Fixes code of conduct link.

Author: korken89

README.md

@@ -125,5 +125,5 @@ Contribution to this crate is organized under the terms of the [Rust Code of
 Conduct][CoC], the maintainer of this crate, the [Cortex-M team][team], promises
 to intervene to uphold that code of conduct.
 
-[CoC]: CODE_OF_CONDUCT.md
+[CoC]: https://www.rust-lang.org/policies/code-of-conduct
 [team]: https://github.com/rust-embedded/wg#the-cortex-m-team