Icon request: Dart

[IoanaAlexandru]

With the popularization of Flutter, Dart is becoming a rather used programming language.

Example brand svg here: https://dart.dev/assets/shared/dart-logo-for-shares.png?2

[amacado]

Hello @IoanaAlexandru, thanks for pointing our Dart! If you got the time feel free to take a look at CONTRIBUTING.md#submitting-icon and add this icon by yourself! :)