[dart][dio] add dateLibrary options ( core, timemachine )

[amondnet]

This pr adds dateLibrary option and simple test to dart-dio generator.
dateLibrary has two options.

• core : dart:core, (default), not handled properly date, date-time format; [BUG] Dart code generator does not support date format for string #2696 I will make a new PR on this.
• timemachine: time_machine

If dateLibrary is timemachine,

input

openapi: 3.0.0
info:
  contact:
    email: amond@amond.net
  description: test
  title: test
  version: 1.0.0
paths:
  /test:
    get:
      responses:
        200:
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DateContainer'
          description: OK

components:
    schemas:
      DateContainer:
        type: object
        properties:
          date:
            format: date
            type: string

output

import 'package:time_machine/time_machine.dart';
import 'package:built_value/built_value.dart';
import 'package:built_value/serializer.dart';

part 'date_container.g.dart';

abstract class DateContainer
    implements Built<DateContainer, DateContainerBuilder> {
  @nullable
  @BuiltValueField(wireName: 'date')
  LocalDate get date;

  // Boilerplate code needed to wire-up generated code
  DateContainer._();

  factory DateContainer([updates(DateContainerBuilder b)]) = _$DateContainer;
  static Serializer<DateContainer> get serializer => _$dateContainerSerializer;
}

@ircecho @swipesight @jaumard @nickmeinhold

--

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
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[wing328]

Please run the following to update the doc as well

"./bin/utils/export_docs_generators.sh"
"./bin/utils/copy-to-website.sh"
"./bin/utils/export_generators_readme.sh

[amondnet]

@wing328 I have updated the documentation.

[nickmeinhold]

Thanks @amondnet!

So guys I don’t use this generator or know much about it.

Personally I think we should be working toward a single dart generator with options rather than continuing to diverge. I respect that others have different opinions but that is where I want to be spending my limited time rather than trying to stay on top of the different generators.

I’m wondering if, rather than getting silence from the technical committee, @wing328 what do you think about asking @athornz and @amondnet if they want to be the technical committee for the dart-dio generator (and would you guys want to?).

Thanks, sorry I'm not more help.

[josh-burton]

Looks good to me, I think this is a nice addition to the generator

[josh-burton]

@nickmeinhold I'm happy to be added to the committee for dart dio.

[amondnet]

@nickcmaynard Yes, I would like to join the committee.

[wing328]

Add @athornz, @amondnet to Dart technical committee via #4800 as both have at least 3 merged PRs for Dart generators.

Thanks for joining us to help move the project forward.