Add required metadata

Author: NoFr1ends

Cargo.toml

@@ -2,6 +2,9 @@
 name = "opengr2"
 version = "0.1.0"
 edition = "2021"
+license = "MIT"
+license-file = "LICENSE"
+description = "A file parser for Granny2 (.gr2) files written in pure rust"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html