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/recorder/recorder.go

@@ -14,6 +14,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// Package recorder defines interfaces for working with Kubernetes event recorders.
+//
+// You can use these to emit Kubernetes events associated with a particular Kubernetes
+// object.
 package recorder
 
 import (