Wait for downstream pipeline of Omnibus build pipeline

Context

release-tools has the module PackagesStatus to check the status of Omnibus package build. It checks the status of a bridge (downstream) pipeline in the Omnibus package build pipeline. This step exists on both monthly and patch release pipelines.

Problem Statements

When the downstream pipeline is not yet reached, the check job fails immediately with "No downstream pipeline..." error (example). It requires the RMs to check the job log to realize the issue, wait for the downstream pipeline to be created, and then retry the check job. It is time consuming and tedious.

We should retry the downstream pipeline wait for some time, to avoid this false positive.

Hints

A similar implementation was done in gitlab-org/release-tools!4248 (merged). We can do the same.

Exit Criteria

• Omnibus package status check waits until the downstream pipeline of the Omnibus build pipeline is created