Add labeler classes for the post-deploy pipeline
What does this MR do and why?
Merge requests should have a label to identify the post-migration
associated has been executed on staging and production. To achieve this,
the Deployments::MergeRequestLabeler
and Deployments::MergeRequestUpdater
classes were moved into the Tracker
namespace so they can be re-shared between Deployments
and
PostMigrations` context.
Related to gitlab-com/gl-infra/delivery#2363 (closed)
Author Check-list
- [-] Has documentation been updated?