chore(deps): update ironbank docker tags to v1.6.0

This MR contains the following updates:

Package	Update	Change
registry1.dso.mil/ironbank/nirmata/kyverno	minor	v1.5.8 -> v1.6.0
registry1.dso.mil/ironbank/nirmata/kyvernopre	minor	v1.5.8 -> v1.6.0

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