Screwdriver: Enable to use HTML <a> tag on a banner

[tk3fftk]

What happened:
We cannot use <a> tag on a banner. A link on banner should be useful.

What you expected to happen:
We can use <a> tag on a banner.

How to reproduce it:
Create a banner with <a> tag or any HTML tags.

[tkyi]

It doesn't look like we do not allow for <a> tag in the data-schema validation. I checked and it looks like <a> is getting encoded at some point, probably in handlebars.

Can probably just change from double {{ to triple {{{ in this file: https://github.com/screwdriver-cd/ui/blob/master/app/components/nav-banner/template.hbs#L7

Ref: http://www.kaspertidemann.com/html-safe-strings-in-handlebars/

[tkyi]

This issue should be fixed with UI: v1.0.453