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/sigs.k8s.io/controller-runtime/pkg/webhook/admission/defaulter.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package admission
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Defaulter defines functions for setting defaults on resources
+type Defaulter interface {
+	runtime.Object
+	Default()
+}
+
+// DefaultingWebhookFor creates a new Webhook for Defaulting the provided type.
+func DefaultingWebhookFor(defaulter Defaulter) *Webhook {
+	return &Webhook{
+		Handler: &mutatingHandler{defaulter: defaulter},
+	}
+}
+
+type mutatingHandler struct {
+	defaulter Defaulter
+	decoder   *Decoder
+}
+
+var _ DecoderInjector = &mutatingHandler{}
+
+// InjectDecoder injects the decoder into a mutatingHandler.
+func (h *mutatingHandler) InjectDecoder(d *Decoder) error {
+	h.decoder = d
+	return nil
+}
+
+// Handle handles admission requests.
+func (h *mutatingHandler) Handle(ctx context.Context, req Request) Response {
+	if h.defaulter == nil {
+		panic("defaulter should never be nil")
+	}
+
+	// Get the object in the request
+	obj := h.defaulter.DeepCopyObject().(Defaulter)
+	err := h.decoder.Decode(req, obj)
+	if err != nil {
+		return Errored(http.StatusBadRequest, err)
+	}
+
+	// Default the object
+	obj.Default()
+	marshalled, err := json.Marshal(obj)
+	if err != nil {
+		return Errored(http.StatusInternalServerError, err)
+	}
+
+	// Create the patch
+	return PatchResponseFromRaw(req.Object.Raw, marshalled)
+}