Update registry1.dso.mil/ironbank/kiwigrid/k8s-sidecar Docker tag to v1.28.4

This MR contains the following updates:

Package	Update	Change
registry1.dso.mil/ironbank/kiwigrid/k8s-sidecar (source)	minor	1.22.4 -> 1.28.4

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Upgrade Notices

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