[NonGNU ELPA] Dart-Mode version 1.0.4

[ELPA update]

Version 1.0.4 of package Dart-Mode has just been released in NonGNU ELPA.
You can now find it in M-x package-list RET.

Dart-Mode describes itself as:
  Major mode for editing Dart files

More at https://elpa.nongnu.org/nongnu/dart-mode.html