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/envtest/helper.go

@@ -0,0 +1,41 @@
+package envtest
+
+import apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
+
+// mergePaths merges two string slices containing paths.
+// This function makes no guarantees about order of the merged slice.
+func mergePaths(s1, s2 []string) []string {
+	m := make(map[string]struct{})
+	for _, s := range s1 {
+		m[s] = struct{}{}
+	}
+	for _, s := range s2 {
+		m[s] = struct{}{}
+	}
+	merged := make([]string, len(m))
+	i := 0
+	for key := range m {
+		merged[i] = key
+		i++
+	}
+	return merged
+}
+
+// mergeCRDs merges two CRD slices using their names.
+// This function makes no guarantees about order of the merged slice.
+func mergeCRDs(s1, s2 []*apiextensionsv1beta1.CustomResourceDefinition) []*apiextensionsv1beta1.CustomResourceDefinition {
+	m := make(map[string]*apiextensionsv1beta1.CustomResourceDefinition)
+	for _, crd := range s1 {
+		m[crd.Name] = crd
+	}
+	for _, crd := range s2 {
+		m[crd.Name] = crd
+	}
+	merged := make([]*apiextensionsv1beta1.CustomResourceDefinition, len(m))
+	i := 0
+	for _, crd := range m {
+		merged[i] = crd
+		i++
+	}
+	return merged
+}