guard against go version linter breakage

[abe-winter]

Checklist

• I think we also need to version the linter cache (sigh). come up with a test case that shows this, then look at env vars

What changed

• add GOVERSION string to the bin/gotools path

Why

On local machines, a golangci-lint build from a previous go version can fail mysteriously. Folks have wasted a lot of energy debugging this.

There is a chance this still won't work -- we are crossing our fingers that the golangci-lint cache is not broken by the rebuild.