Make the dropdown of GitHub Actions a single button, if there's only one action

[tunnckoCore]

Here you should see a dropdwon "Re-run checks", which has only one item "Re-run all checks". I propose to make the dropdown a button "Re-run all checks" directly. At least for now, until we get more items in that dropdown.

More: https://twitter.com/tunnckoCore/status/1197456822891896833

[fregante]

This feature should be something like:

if dropdown has 1 action
	add 'btn' class to action
	dropdown.replaceWith(action)

[mehrdadn]

Just wanted to request that there also be a button for canceling the run :)

[tunnckoCore]

@fregante true. For future-proofing

[tunnckoCore]

😍