[CLC-4079] Update gems: secure_headers & angular-gem

https://jira.ets.berkeley.edu/jira/browse/CLC-4079

**Note**: We should probably wait to merge until the QA branch has been cut for sprint 44.
Merge pull request #2791 from christianv/CLC-4079

[CLC-4079] Update gems: secure_headers & angular-gem