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-tools/pkg/schemapatcher/internal/yaml/nested.go

@@ -0,0 +1,87 @@
+/*
+Copyright 2019 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 yaml
+
+import (
+	"fmt"
+
+	"gopkg.in/yaml.v3"
+)
+
+// ValueInMapping finds the value node with the corresponding string key
+// in the given mapping node.  If the given node is not a mapping, an
+// error will be returned.
+func ValueInMapping(root *yaml.Node, key string) (*yaml.Node, error) {
+	if root.Kind != yaml.MappingNode {
+		return nil, fmt.Errorf("unexpected non-mapping node")
+	}
+
+	for i := 0; i < len(root.Content)/2; i++ {
+		keyNode := root.Content[i*2]
+		if keyNode.Value == key {
+			return root.Content[i*2+1], nil
+		}
+	}
+	return nil, nil
+}
+
+// asCloseAsPossible goes as deep on the given path as possible, returning the
+// last node that existed from the given path in the given tree of mapping
+// nodes, as well as the rest of the path that could not be fetched, if any.
+func asCloseAsPossible(root *yaml.Node, path ...string) (*yaml.Node, []string, error) {
+	if root == nil {
+		return nil, path, nil
+	}
+	if root.Kind == yaml.DocumentNode && len(root.Content) > 0 {
+		root = root.Content[0]
+	}
+
+	currNode := root
+	for ; len(path) > 0; path = path[1:] {
+		if currNode.Kind != yaml.MappingNode {
+			return nil, nil, fmt.Errorf("unexpected non-mapping (%v) before path %v", currNode.Kind, path)
+		}
+
+		nextNode, err := ValueInMapping(currNode, path[0])
+		if err != nil {
+			return nil, nil, fmt.Errorf("unable to get next node in path %v: %v", path, err)
+		}
+
+		if nextNode == nil {
+			// we're as close as possible
+			break
+		}
+
+		currNode = nextNode
+	}
+
+	return currNode, path, nil
+}
+
+// GetNode gets the node at the given path in the given sequence of mapping
+// nodes, or, if it doesn't exist, returning false.
+func GetNode(root *yaml.Node, path ...string) (*yaml.Node, bool, error) {
+	resNode, restPath, err := asCloseAsPossible(root, path...)
+	if err != nil {
+		return nil, false, err
+	}
+	// more path means the node didn't exist
+	if len(restPath) != 0 {
+		return nil, false, nil
+	}
+	return resNode, true, nil
+}