Update containers/image v5.3.1

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/gorilla/mux/test_helpers.go

@@ -1,19 +0,0 @@
-// Copyright 2012 The Gorilla Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package mux
-
-import "net/http"
-
-// SetURLVars sets the URL variables for the given request, to be accessed via
-// mux.Vars for testing route behaviour. Arguments are not modified, a shallow
-// copy is returned.
-//
-// This API should only be used for testing purposes; it provides a way to
-// inject variables into the request context. Alternatively, URL variables
-// can be set by making a route that captures the required variables,
-// starting a server and sending the request to that server.
-func SetURLVars(r *http.Request, val map[string]string) *http.Request {
-	return setVars(r, val)
-}