Bump version of UAA to 1.6.1 for two important bug fixes
https://www.pivotaltracker.com/story/show/68847076 - add in correct length for usernames in the approvals table
https://www.pivotaltracker.com/story/show/69144738 - correctly handle secret changes when authentication for the old secret fails
Merge remote-tracking branch 'origin/pr/351' into develop