WP Featherlight + tabindex

Featherlight doesn’t seem to play nicely with tabindex, which is a bummer when using it for modal forms.

I found this github issue: https://github.com/noelboss/featherlight/issues/285 and related stackoverflow question: https://stackoverflow.com/questions/42234790/how-can-i-configure-featherlight-to-support-tabindex-within-the-modal

Is there a way to incorporate this fix/edit into the WP version?