Allow attaching widgets to elements other than buttons

It seems we can only trigger the changelog widget from a button HTML element with the data data-featurebase-changelog.

It would be useful to be able to trigger and attach the widget to other HTML elements.

I saw the button tag is hard-coded in the SDK and it may work by updating
document.querySelectorAll("button[data-featurebase-changelog]");
to
document.querySelectorAll("[data-featurebase-changelog]");