mattermost update to 7.8.0-bb.0

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/mattermost/-/blob/7.8.0-bb.0/CHANGELOG.md

Package MR

big-bang/product/packages/mattermost!113 (merged)

For Issue

Closes big-bang/product/packages/mattermost#63 (closed)

added botmr mattermost statusreview labels

assigned to @chris.hayter

changed the description

requested review from @micah.nagel, @ryan.j.garcia, and @rob.ferguson

marked this merge request as ready

changed the description

changed milestone to %1.55.0

approved this merge request

enabled an automatic merge when the pipeline for 91affcb0 succeeds

merged

mentioned in commit c6b18ccd