chore: run CI with go 1.18
Created by: camdencheek
The first step towards using go 1.18 is building with 1.18 in CI. This does not yet update our project's go mod version, so no new language features from go 1.18 will be available. However, it does mean things deprecated in go 1.18 will show up as lint errors.
Test plan
Ran it through main-dry-run