Migrate to GitHub actions

[wincent]

Not sure whether this will be easy or hard, so consider this "wish list".

Motivation: our team doesn't have admin permissions on the Travis integration, so when things go wrong, we often get stuck. Also, GitHub actions are likely to be more stable/reliable/fast. See https://github.com/liferay/liferay-npm-tools/issues/307 for a ticket that summarizes our migration to GitHub actions in other repos.