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/storage/etcd3/watcher.go

@@ -56,9 +56,15 @@ func testingDeferOnDecodeError() {
 
 func init() {
 	// check to see if we are running in a test environment
+	TestOnlySetFatalOnDecodeError(true)
 	fatalOnDecodeError, _ = strconv.ParseBool(os.Getenv("KUBE_PANIC_WATCH_DECODE_ERROR"))
 }
 
+// TestOnlySetFatalOnDecodeError should only be used for cases where decode errors are expected and need to be tested. e.g. conversion webhooks.
+func TestOnlySetFatalOnDecodeError(b bool) {
+	fatalOnDecodeError = b
+}
+
 type watcher struct {
 	client      *clientv3.Client
 	codec       runtime.Codec