Stop supporting 2.8
This lifts the requirement for core and staging dependencies to 2.9 and drops support for 2.8. It also removes all checks for versions >=2.9, all code for older versions, and the CI job for 2.8.
This lifts the requirement for core and staging dependencies to 2.9 and drops support for 2.8. It also removes all checks for versions >=2.9, all code for older versions, and the CI job for 2.8.