update kube and vendor dependencies

With kubernetes 1.18 release of client-go, signatures on methods in
generated clientsets, dynamic, metadata, and scale clients have been
modified to accept context.Context as a first argument.
Signatures of Create, Update, and Patch methods have been updated
to accept CreateOptions, UpdateOptions and PatchOptions respectively.
Signatures of Delete and DeleteCollection methods now accept
DeleteOptions by value instead of by reference.
These changes are now accommodated with this PR and client-go
and dependencies are updated to v1.18.0

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

vendor/google.golang.org/grpc/service_config.go

@@ -136,9 +136,9 @@ type retryPolicy struct {
 	maxAttempts int
 
 	// Exponential backoff parameters. The initial retry attempt will occur at
-	// random(0, initialBackoffMS). In general, the nth attempt will occur at
+	// random(0, initialBackoff). In general, the nth attempt will occur at
 	// random(0,
-	//   min(initialBackoffMS*backoffMultiplier**(n-1), maxBackoffMS)).
+	//   min(initialBackoff*backoffMultiplier**(n-1), maxBackoff)).
 	//
 	// These fields are required and must be greater than zero.
 	initialBackoff    time.Duration