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/server/mux/OWNERS

@@ -1,2 +1,4 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
 reviewers:
 - sttts

vendor/k8s.io/apiserver/pkg/server/mux/doc.go

@@ -15,4 +15,4 @@ limitations under the License.
 */
 
 // Package mux contains abstractions for http multiplexing of APIs.
-package mux
+package mux // import "k8s.io/apiserver/pkg/server/mux"

vendor/k8s.io/apiserver/pkg/server/mux/pathrecorder.go

@@ -55,7 +55,7 @@ type PathRecorderMux struct {
 	pathStacks map[string]string
 }
 
-// pathHandler is an http.Handler that will satify requests first by exact match, then by prefix,
+// pathHandler is an http.Handler that will satisfy requests first by exact match, then by prefix,
 // then by notFoundHandler
 type pathHandler struct {
 	// muxName is used for logging so you can trace requests through