mattermost update to 7.8.1-bb.0

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/mattermost/-/blob/7.8.1-bb.0/CHANGELOG.md

Package MR

big-bang/product/packages/mattermost!114 (merged)

For Issue

Closes big-bang/product/packages/mattermost#64 (closed)

added botmr mattermost statusreview labels

changed the description

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

assigned to @chris.hayter

changed milestone to %1.56.0

changed the description

marked this merge request as ready

approved this merge request

merged

mentioned in commit 15c82732