dart2 client not compiling and ignoring templateDir

[alexnavratil]

Description

The dart client generator overwrites a custom set templateDir when using dart 2.x. The default dart2 templates also fail to compile since they depend on some old and already deleted dependency (dartson).

openapi-generator version

<=4.1.0 and master

OpenAPI declaration file content or url

/

Command line used for generation

openapi-generator generate -o api -g dart -i openapi-backend.yml -t

Steps to reproduce

Use the command from above with a model like this:

SomeEnum:
      type: string
      enum:
        - left
        - right
        - center

Related issues/PRs

fixes and used some changes from #2830

Suggest a fix/enhancement

see PR

[auto-labeler]

👍 Thanks for opening this issue!
🏷 I have applied any labels matching special text in your issue.

The team will review the labels and make any necessary changes.