SKIP UPGRADE: Update Ironbank to v15.8.1

This MR contains the following updates:

Package	Update	Change
ironbank/gitlab/gitlab-runner/gitlab-runner	minor	15.7.3 -> v15.8.1
ironbank/gitlab/gitlab-runner/gitlab-runner	minor	v15.7.3 -> v15.8.1
registry1.dso.mil/ironbank/gitlab/gitlab-runner/gitlab-runner	minor	v15.7.3 -> v15.8.1
registry1.dso.mil/ironbank/gitlab/gitlab-runner/gitlab-runner-helper	minor	v15.7.3 -> v15.8.1

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