build: Bump version to 1.21.0-rc1, Dockerfile changes · kubewarden/policy-server@8322340

ubuntu-latest pipelines will use ubuntu-24.04 soon. For more details, see https://github.com/actions/runner-images/issues/10636

"pull_request_target.opened" is not a known webhook name (https://developer.github.com/v3/activity/events/types/)

"pull_request_target.reopened" is not a known webhook name (https://developer.github.com/v3/activity/events/types/)

"pull_request_target.synchronize" is not a known webhook name (https://developer.github.com/v3/activity/events/types/)

"pull_request_target.edited" is not a known webhook name (https://developer.github.com/v3/activity/events/types/)

Provide feedback