Use latest released core_arch version

Author: GabrielMajeri

Cargo.toml

@@ -22,7 +22,7 @@ maintenance = { status = "experimental" }
 
 [dependencies]
 cfg-if = "0.1.10"
-core_arch = { git = "https://github.com/rust-lang/stdarch", optional = true }
+core_arch = { version = "0.1.5", optional = true }
 libm = "0.1.4"
 
 [features]