message: update license in Cargo.toml
diff: @@ -5,8 +5,8 @@ documentation = "http://www.poumeyrol.fr/doc/opencv-rust/opencv/index.html"
  repository = "https://github.com/kali/opencv-rust"
  readme = "README.md"
  keywords = [ "opencv", "vision" ]
  -license = "WTFPL"
  -version = "0.3.0"
  +license = "MIT"
  +version = "0.4.0"
  edition = "2018"
  authors = ["Mathieu Poumeyrol <kali@zoy.org>"]
  build = "build.rs"
  