add license data to libstd

Include the license of libstd in the cargo metadata

Author: cardoe

src/libstd/Cargo.toml

@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 name = "std"
 version = "0.0.0"
 build = "build.rs"
+license = "MIT/Apache-2.0"
 
 [lib]
 name = "std"