Re-implement invalidate_on_push using supported APIs (#602, #612)
The invalidate_on_push option now uses the creation timestamps of commit statuses to estimate the push time instead of the deprecated and removed pushedDate GraphQL field. This should work in most practical cases, but may ignore some approvals that occur immediately after a push. See the README for more details.
The do_not_load_commit_pushed_date option introduced in version 1.30.0 is now deprecated. While the option is still recognized in configuration files, it has no effect.