dev/ci: only asdf install go in pipeline gen
Created by: bobheadxi
Cuts the pipeline generation step from ~60s to ~25s - doing a fresh asdf install golang seems significantly faster than using the asdf tools cache.
Opened a related idea: https://github.com/sourcegraph/sourcegraph/issues/33854
Together with https://github.com/sourcegraph/sourcegraph/pull/33821 , this significantly reduces the time it takes for builds to get to the "actually running" state (~120s -> ~50s)