Add 'go vet' to pipeline and fix warning

.drone.yml

@@ -9,6 +9,7 @@ steps:
    environment:
      CGO_ENABLED: 0
    commands:
+    - go vet
     - go build
 
  - name: upload

dns.go

@@ -394,7 +394,11 @@ func (s *DNSServer) Query() *DNSResult {
 
 	// query the dn42 root zone SOA
 	msg.Question = []dns.Question{
-		{"dn42.", dns.TypeSOA, dns.ClassINET},
+		dns.Question{
+			Name:   "dn42.",
+			Qtype:  dns.TypeSOA,
+			Qclass: dns.ClassINET,
+		},
 	}
 
 	// add EDNS0 options to also query the service ID (NSID)