Update Ironbank to v2.7.0

This MR contains the following updates:

Package	Update	Change
ironbank/opensource/grafana/promtail	minor	2.6.1 -> v2.7.0
registry1.dso.mil/ironbank/opensource/grafana/promtail	minor	v2.6.1 -> v2.7.0

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Relates to #8 (closed)