jenkinsfile: Don't even allocate a Windows worker if there aren't Go changes.
jenkinsfile: Don't even allocate a Windows worker if there aren't Go changes.

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client