* test dart 1x in drone
* update dart image
* trigger build failure
* Revert "trigger build failure"
This reverts commit d565f348ba120d9111b7ad2c6f7e3ad077197a26.
* add dart 2 test
* update build runner version
* test dart2
* only test dart jaguar
* remove pubspec.lock
* better wording
* use pub run test
* revert changes in build_runner
* update test in pom.xml
* update samples
* add dart scripts to ensure up-to-date
* fix: set fields to null if json value is null.
* rebuild dart2 petstore
* rebuild dart petstore
* rebuild petstore
* [DART]fix: set fields to null if json value is null.