Link QA failure issues to the announcements threads in slack
Proposal
In #2911 (closed) we automated opening release/task issues for QA failure on gstg-cny and gprd-cny. The issues are created and assigned to release managers.
In this issue, we'd like to improve the experience by posting a message to the associated slack thread in #announcements
that contains a link to the issue.
This is the class the posts the failure message: https://gitlab.com/gitlab-org/release-tools/-/blob/a099cae4489f5511b448fbe579e98c48210304be/lib/release_tools/slack/qa_notification.rb.