Make more "clickable"

[blackary]

This card seems great, but it feels like it's meant to be "clickable", and was missing a couple of things:

• There's no indication when you click it of anything happening (other than the value changing from None to True)
• It seems like there should be the ability to add a url

This adds the ability to go to a url, adds a darker border while clicking, and makes it more button-like by starting out at False, and changing to True on click.

(Sorry for all the linting changes -- I can undo those if you'd like)

[gamcoh]

This is great! Thank you!

I just added a new commit with the version bumped and the new URL feature displayed in the README