feat(associations): add unlicense files to license icon

[tahirmurata]

Adds support for unlicense and unlicence files to have the license icon. https://unlicense.org

[tahirmurata]

From the unlicense website:

You would traditionally put the above statement into a file named COPYING or LICENSE. However, to explicitly distance yourself from the whole concept of copyright licensing, we recommend that you put your unlicensing statement in a file named UNLICENSE.

[uncenter]

I think you want to call this PR feat(associations): add unlicense files to license icon, since your current title implies the addition of a new SVG icon.