Update Ironbank for OPA gatekeeper

This MR contains the following updates:

Package	Update	Change
gluon	minor	0.4.9 -> 0.5.0
ironbank/opensource/openpolicyagent/gatekeeper (source)	minor	v3.15.1 -> v3.16.0
registry1.dso.mil/ironbank/opensource/kubernetes/kubectl (source)	patch	v1.29.3 -> v1.29.4
registry1.dso.mil/ironbank/opensource/openpolicyagent/gatekeeper (source)	minor	v3.15.1 -> v3.16.0

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Upgrade Notices

(Include any relevant notes about upgrades here or write "N/A" if there are none) N/A