Add format:verify back to GitHub Actions push.yml

[JoshuaKGoldberg]

trafficstars

I removed it from https://github.com/JoshuaKGoldberg/TypeStat/pull/1011 because it constantly complained about at least one file being off in a way I couldn't figure out. Annoying.

https://github.com/JoshuaKGoldberg/TypeStat/runs/4129272214?check_suite_focus=true

$ yarn prettier --list-different "**/*.{js,json,md,ts,yml}"
$ /home/runner/work/TypeStat/TypeStat/node_modules/.bin/prettier --list-different '**/*.{js,json,md,ts,yml}'
src/mutations/typeMutating/createNonNullAssertion.ts
error Command failed with exit code 1.