`update-pr-from-base-branch` uses the wrong icon in its "Resolve conflicts" #3862

The icon in "Resolve conflicts" used by update-pr-from-base-branch no longer matches the native one.

Comparison screenshot here (native on top):

<img width="609" alt="Screen Shot 3" src="https://user-images.githubusercontent.com/1402241/103714900-cb4c8880-4f84-11eb-8842-85ae5f24854d.png">

Currently testable on https://github.com/sindresorhus/refined-github/pull/3855 until https://github.com/sindresorhus/refined-github/issues/3861 is resolved.

I think this button only appears on draft PRs since GitHub doesn't show the native "Resolve conflict" there