Update to latest alloc-cortex-m

Author: phil-opp

Cargo.lock

@@ -16,7 +16,7 @@ r0 = "0.1.0"
 spin = "0.4.5"
 volatile = "0.2.1"
 rusttype = {git = "https://github.com/phil-opp/rusttype.git", branch = "no_std"}
-alloc-cortex-m = {git = "https://github.com/embed-rs/alloc-cortex-m.git", branch = "master" }
+alloc-cortex-m = "0.3.3"
 bitflags = "0.7.0"
 
 [dependencies.arrayvec]