Fix crates.io badge

Author: atouchet

README.md

@@ -1,6 +1,6 @@
 This is an mp4 track metadata parser.
 
-[![Latest crate version](https://meritbadge.herokuapp.com/mp4parse)](https://crates.io/crates/mp4parse)
+[![Latest crate version](https://img.shields.io/crates/v/mp4parse.svg)](https://crates.io/crates/mp4parse)
 [![Travis build status](https://travis-ci.org/mozilla/mp4parse-rust.svg)](https://travis-ci.org/mozilla/mp4parse-rust)
 
 Our primary interest is writing a pure-rust replacement for the