build: use upstream's xgo image
build: use upstream's xgo image

This is reasonably safe now that they have basic smoke tests.

vaibhavarora/cockroach,glycerine/cockroach,sunya123/cockroach,vaibhavarora/cockroach,petermattis/cockroach,petermattis/cockroach,glycerine/cockroach,maxlang/cockroach,arjun4084346/cockroach,sunya123/cockroach,paperstreet/cockroach,arjun4084346/cockroach,maxlang/cockroach,veteranlu/cockroach,cockroachdb/cockroach,sunya123/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,sunya123/cockroach,arjun4084346/cockroach,maxlang/cockroach,sunya123/cockroach,vaibhavarora/cockroach,vivekmenezes/cockroach,petermattis/cockroach,vivekmenezes/cockroach,arjun4084346/cockroach,veteranlu/cockroach,veteranlu/cockroach,maxlang/cockroach,veteranlu/cockroach,glycerine/cockroach,petermattis/cockroach,paperstreet/cockroach,petermattis/cockroach,cockroachdb/cockroach,sunya123/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,cockroachdb/cockroach,petermattis/cockroach,paperstreet/cockroach,glycerine/cockroach,petermattis/cockroach,cockroachdb/cockroach,maxlang/cockroach,veteranlu/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,sunya123/cockroach,paperstreet/cockroach,vivekmenezes/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,glycerine/cockroach,arjun4084346/cockroach,glycerine/cockroach,glycerine/cockroach,maxlang/cockroach,veteranlu/cockroach,cockroachdb/cockroach,vivekmenezes/cockroach,vivekmenezes/cockroach,arjun4084346/cockroach,vaibhavarora/cockroach,cockroachdb/cockroach,petermattis/cockroach,arjun4084346/cockroach,glycerine/cockroach,maxlang/cockroach,sunya123/cockroach,vaibhavarora/cockroach,arjun4084346/cockroach,cockroachdb/cockroach,paperstreet/cockroach,maxlang/cockroach,paperstreet/cockroach,cockroachdb/cockroach,paperstreet/cockroach,vivekmenezes/cockroach