Update gitlab_git to version 5.7.1

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
 Merge branch 'fix-discover-branch' into 'master'

Fix Discover Branch

Fixes #1073
Sort projects by activity at group show page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
 Merge branch 'fix-group-projects-sort' into 'master'

Sort projects by activity at group show page