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/kube-openapi/pkg/generators/extension.go

@@ -32,6 +32,7 @@ type extensionAttributes struct {
 	xName         string
 	kind          types.Kind
 	allowedValues sets.String
+	enforceArray  bool
 }
 
 // Extension tag to openapi extension attributes
@@ -46,8 +47,9 @@ var tagToExtension = map[string]extensionAttributes{
 		allowedValues: sets.NewString("merge", "retainKeys"),
 	},
 	"listMapKey": {
-		xName: "x-kubernetes-list-map-keys",
-		kind:  types.Slice,
+		xName:        "x-kubernetes-list-map-keys",
+		kind:         types.Slice,
+		enforceArray: true,
 	},
 	"listType": {
 		xName:         "x-kubernetes-list-type",
@@ -113,6 +115,10 @@ func (e extension) hasMultipleValues() bool {
 	return len(e.values) > 1
 }
 
+func (e extension) isAlwaysArrayFormat() bool {
+	return tagToExtension[e.idlTag].enforceArray
+}
+
 // Returns sorted list of map keys. Needed for deterministic testing.
 func sortedMapKeys(m map[string][]string) []string {
 	keys := make([]string, len(m))