What's Changed
* Instance generic empty case by wild-endeavor in https://github.com/flyteorg/flytekit/pull/2802
* More instance generic checks (2813) by eapolinario in https://github.com/flyteorg/flytekit/pull/2817
* fix is_optional_type or not return true for all union types (2824) by eapolinario in https://github.com/flyteorg/flytekit/pull/2825
* Run tests on merges to release branches by eapolinario in https://github.com/flyteorg/flytekit/pull/2826
**Full Changelog**: https://github.com/flyteorg/flytekit/compare/v1.13.8...v1.13.9