generated code should not produce any lint warnings

[sgehrman]

I'm seeing warnings for unnecessary parens, and prefer const in the example mapper.g.dart.

I would be great to get this fixed. I like all my code to be clean and warning free.

[D10100111001]

The package has been updated for null safety. Let me know if this is still an issue. If so, I'll see if I can revisit but this is low priority so will do it when I get a chance. PRs are welcome.

[sgehrman]

I'm still having one last issue.

Try adding avoid_dynamic_calls: true

and see if you see it. There's a line in my mapper file that does something like json['x'] that needs to be (json['x'] as String)