Add a versioned alias dart@2.16 for the current version (#107)
Add a versioned alias dart@2.16 for the current version (#107)

* Add a versioned alias dart@2.16 for the current version

A new check in Homebrew requires that the current version have
an alias with a version number, if we have other versions with numbers.
dart-lang/homebrew-dart,dart-lang/homebrew-dart,dart-lang/homebrew-dart