json_serializable upgrade

[feduke-nukem]

json_serializable have been updated to 6.6.0 recently with some improvements of JsonKey annotation

Is it possible to upgrade dependencies?

Related pull-request

[SunlightBro]

It's not a major-version upgrade, so it might simply already work.
You can run the tests in this repo or watch the next build.

[SunlightBro]

@feduke-nukem FYI I've run
dart pub get && dart test in /freezed

Building package executable... (2.5s)
Built test:test.
00:07 +304 ~1: All tests passed! 

also dart pub outdated shows

Showing outdated packages.
[*] indicates versions that are not the latest available.

Package Name        Current              Upgradable           Resolvable           Latest  

direct dependencies:
freezed_annotation  *2.2.0 (overridden)  *2.2.0 (overridden)  *2.2.0 (overridden)  2.2.0   

dev_dependencies:  
build_runner        *2.3.3               *2.3.3               *2.3.3               2.4.0   
You are already using the newest resolvable versions listed in the 'Resolvable' column.
Newer versions, listed in 'Latest', may not be mutually compatible.