promtail update to 6.15.5-bb.1

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/promtail/-/blob/6.15.5-bb.1/CHANGELOG.md

Package MR

big-bang/product/packages/promtail!70

For Issue

Closes big-bang/product/packages/promtail#24

Upgrade Notices

N/A