Error during install on MacOS

[ResistanceIsUseless]

!  ~/g/bin  go get -u "github.com/haccer/subjack" 515ms  Tue Jul 2 22:47:19 2019
github.com/miekg/dns
../src/github.com/miekg/dns/dnssec_keyscan.go:260:7: undefined: strings.Builder
../src/github.com/miekg/dns/msg_helpers.go:271:8: undefined: strings.Builder
../src/github.com/miekg/dns/serve_mux.go:43:9: undefined: strings.Builder
../src/github.com/miekg/dns/types.go:440:10: undefined: strings.Builder
../src/github.com/miekg/dns/types.go:464:10: undefined: strings.Builder
../src/github.com/miekg/dns/types.go:492:10: undefined: strings.Builder
../src/github.com/miekg/dns/types.go:513:29: undefined: strings.Builder
../src/github.com/miekg/dns/types.go:523:28: undefined: strings.Builder

[ResistanceIsUseless]

Just needed to update go, didnt realize i was running 1.9.