Formatter Check and DartDoc Upload

[maxxfrazer]

• add dart format to build process
• upload zipped dartdoc on release

[littleGnAl]

I'm not very sure if the action k-paxian/dart-package-publisher@master brings the dart env or not. Maybe we need to test it first.

[maxxfrazer]

I've aded a step to build.yml to attach it to the workflow. If that works, then this one should work the same…

[littleGnAl]

I think it's not the same, in the build.yaml, you have set up the dart env by using the action uses: dart-lang/setup-dart@v1, I think you should also add it here.