message: chore: add minimum rust version to the ink crate, refs
diff: @@ -3,6 +3,7 @@ name = "ink"
  version = "4.0.0-beta"
  authors = ["Parity Technologies <admin@parity.io>", "Robin Freyler <robin@parity.io>"]
  edition = "2021"
  +rust-version = "1.63"
  license = "Apache-2.0"
  readme = "README.md"
  