add golangci-lint linter (#5499)

plugin/kubernetes/kubernetes.go

@@ -96,7 +96,6 @@ var (
 func (k *Kubernetes) Services(ctx context.Context, state request.Request, exact bool, opt plugin.Options) (svcs []msg.Service, err error) {
 	// We're looking again at types, which we've already done in ServeDNS, but there are some types k8s just can't answer.
 	switch state.QType() {
-
 	case dns.TypeTXT:
 		// 1 label + zone, label must be "dns-version".
 		t, _ := dnsutil.TrimZone(state.Name(), state.Zone)
@@ -216,7 +215,6 @@ func (k *Kubernetes) getClientConfig() (*rest.Config, error) {
 	}
 	cc.ContentType = "application/vnd.kubernetes.protobuf"
 	return cc, err
-
 }
 
 // InitKubeCache initializes a new Kubernetes cache.
@@ -542,7 +540,6 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
 
 				for _, eps := range ep.Subsets {
 					for _, addr := range eps.Addresses {
-
 						// See comments in parse.go parseRequest about the endpoint handling.
 						if r.endpoint != "" {
 							if !match(r.endpoint, endpointHostname(addr, k.endpointNameMode)) {