Remove doc of master link (#11)

README.md

@@ -3,7 +3,6 @@
 [![Test Status](https://github.com/rust-random/rand/actions/workflows/test.yml/badge.svg?event=push)](https://github.com/rust-random/rand/actions)
 [![Latest version](https://img.shields.io/crates/v/rand_distr.svg)](https://crates.io/crates/rand_distr)
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
-[![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_distr)
 [![API](https://docs.rs/rand_distr/badge.svg)](https://docs.rs/rand_distr)
 
 Implements a full suite of random number distribution sampling routines.
@@ -39,7 +38,6 @@ can be enabled. (Note that any other crate depending on `num-traits` with the
 
 ## Links
 
--   [API documentation (master)](https://rust-random.github.io/rand/rand_distr)
 -   [API documentation (docs.rs)](https://docs.rs/rand_distr)
 -   [Changelog](CHANGELOG.md)
 -   [The Rand project](https://github.com/rust-random/rand)