actions: update github workflows to use go1.18
Created by: keegancsmith
We haven't yet upgraded to 1.18 on buildkite. However, we should be able to update in github actions. There shouldn't be any issues around these being out of sync, and this reduces the amount that changes in one go when we move asdf to 1.18.
fastmod --hidden '(go-version.*)(\b1\.17\b)' '${1}1.18'
Test Plan: CI is green