vendor: update docker cadvisor winterm

This vendor change was purely for the changes in docker to allow for
setting the Masked and Read-only paths.

See: moby/moby#36644

But because of the docker dep update it also needed cadvisor to be
updated and winterm due to changes in pkg/tlsconfig in docker

See: google/cadvisor#1967

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/docker/client/swarm_inspect.go

@@ -1,10 +1,10 @@
 package client
 
 import (
+	"context"
 	"encoding/json"
 
 	"github.com/docker/docker/api/types/swarm"
-	"golang.org/x/net/context"
 )
 
 // SwarmInspect inspects the swarm.