Update to Go 1.19.6
Created by: jhchabran
Update to 1.19.6 because it fixes a bunch of CVEs.
Created by Sourcegraph batch change jhchabran/update-to-go-1.19.6
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It seems that we're targeting go 1.18.x, so I only added a small test for that branch but kept the rest with 1.18.x. Is that ok?
Test Plan: CI