Update go dependencies

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

@@ -20,9 +20,24 @@
 // symbols to avoid circular dependencies.
 package internal
 
+import "golang.org/x/net/context"
+
 var (
 	// WithContextDialer is exported by clientconn.go
 	WithContextDialer interface{} // func(context.Context, string) (net.Conn, error) grpc.DialOption
 	// WithResolverBuilder is exported by clientconn.go
 	WithResolverBuilder interface{} // func (resolver.Builder) grpc.DialOption
+	// HealthCheckFunc is used to provide client-side LB channel health checking
+	HealthCheckFunc func(ctx context.Context, newStream func() (interface{}, error), reportHealth func(bool), serviceName string) error
+)
+
+const (
+	// CredsBundleModeFallback switches GoogleDefaultCreds to fallback mode.
+	CredsBundleModeFallback = "fallback"
+	// CredsBundleModeBalancer switches GoogleDefaultCreds to grpclb balancer
+	// mode.
+	CredsBundleModeBalancer = "balancer"
+	// CredsBundleModeBackendFromBalancer switches GoogleDefaultCreds to mode
+	// that supports backend returned by grpclb balancer.
+	CredsBundleModeBackendFromBalancer = "backend-from-balancer"
 )