use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/k8s.io/apiserver/pkg/server/options/audit.go

@@ -148,9 +148,14 @@ type AuditWebhookOptions struct {
 	GroupVersionString string
 }
 
+// AuditDynamicOptions control the configuration of dynamic backends for audit events
 type AuditDynamicOptions struct {
 	// Enabled tells whether the dynamic audit capability is enabled.
 	Enabled bool
+
+	// Configuration for batching backend. This is currently only used as an override
+	// for integration tests
+	BatchConfig *pluginbuffered.BatchConfig
 }
 
 func NewAuditOptions() *AuditOptions {
@@ -174,7 +179,8 @@ func NewAuditOptions() *AuditOptions {
 			GroupVersionString: "audit.k8s.io/v1",
 		},
 		DynamicOptions: AuditDynamicOptions{
-			Enabled: false,
+			Enabled:     false,
+			BatchConfig: plugindynamic.NewDefaultWebhookBatchConfig(),
 		},
 	}
 }
@@ -634,7 +640,7 @@ func (o *AuditDynamicOptions) newBackend(
 
 	dc := &plugindynamic.Config{
 		Informer:       informer,
-		BufferedConfig: plugindynamic.NewDefaultWebhookBatchConfig(),
+		BufferedConfig: o.BatchConfig,
 		EventConfig: plugindynamic.EventConfig{
 			Sink: eventSink,
 			Source: corev1.EventSource{