Update admin gem to 1.1.6

* Fix GillSans font stack
Merge pull request #272 from alphagov/bump-admin-gem

Update admin gem to 1.1.6
Allow Editor notes to have tags

www.agileplannerapp.com/boards/173808/cards/5154

Editor's notes were being validated as govspeak
causing safe html checks to fail. We've made an
exception in the SafeHTMLValidator to validate
only govspeak fields:

https://github.com/alphagov/govuk_content_models/pull/236
Move beta flag to be alongside title
Simplify title attributes on links and editions

Title help text isn’t necessary and distracts from table interactions
Add important notes to publication tables

Quickly see important notes without needing to navigate to the
publication
Improve styles of important notes

* Remove divider between title and tabs, the tabs themselves this
distinction
* Give the important note a title and make it less garish
Merge pull request #274 from alphagov/important-notes-tweaks

Improve design of important notes
Merge pull request #273 from alphagov/bump-content-models-for-safe-html-change

Allow Editor notes to have tags