Bump gorilla mux to 1.6.2

**What**
- Update the gopkg.toml

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

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

@@ -13,8 +13,11 @@ import (
 )
 
 var (
+	// ErrMethodMismatch is returned when the method in the request does not match
+	// the method defined against the route.
 	ErrMethodMismatch = errors.New("method is not allowed")
-	ErrNotFound       = errors.New("no matching route was found")
+	// ErrNotFound is returned when no route match is found.
+	ErrNotFound = errors.New("no matching route was found")
 )
 
 // NewRouter returns a new router instance.
@@ -63,6 +66,8 @@ type Router struct {
 	KeepContext bool
 	// see Router.UseEncodedPath(). This defines a flag for all routes.
 	useEncodedPath bool
+	// Slice of middlewares to be called after a match is found
+	middlewares []middleware
 }
 
 // Match attempts to match the given request against the router's registered routes.
@@ -79,6 +84,12 @@ type Router struct {
 func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
 	for _, route := range r.routes {
 		if route.Match(req, match) {
+			// Build middleware chain if no error was found
+			if match.MatchErr == nil {
+				for i := len(r.middlewares) - 1; i >= 0; i-- {
+					match.Handler = r.middlewares[i].Middleware(match.Handler)
+				}
+			}
 			return true
 		}
 	}
@@ -87,9 +98,9 @@ func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
 		if r.MethodNotAllowedHandler != nil {
 			match.Handler = r.MethodNotAllowedHandler
 			return true
-		} else {
-			return false
 		}
+
+		return false
 	}
 
 	// Closest match for a router (includes sub-routers)
@@ -147,6 +158,7 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if !r.KeepContext {
 		defer contextClear(req)
 	}
+
 	handler.ServeHTTP(w, req)
 }
 
@@ -164,13 +176,18 @@ func (r *Router) GetRoute(name string) *Route {
 // StrictSlash defines the trailing slash behavior for new routes. The initial
 // value is false.
 //
-// When true, if the route path is "/path/", accessing "/path" will redirect
+// When true, if the route path is "/path/", accessing "/path" will perform a redirect
 // to the former and vice versa. In other words, your application will always
 // see the path as specified in the route.
 //
 // When false, if the route path is "/path", accessing "/path/" will not match
 // this route and vice versa.
 //
+// The re-direct is a HTTP 301 (Moved Permanently). Note that when this is set for
+// routes with a non-idempotent method (e.g. POST, PUT), the subsequent re-directed
+// request will be made as a GET by most clients. Use middleware or client settings
+// to modify this behaviour as needed.
+//
 // Special case: when a route sets a path prefix using the PathPrefix() method,
 // strict slash is ignored for that route because the redirect behavior can't
 // be determined from a prefix alone. However, any subrouters created from that
@@ -196,10 +213,6 @@ func (r *Router) SkipClean(value bool) *Router {
 // UseEncodedPath tells the router to match the encoded original path
 // to the routes.
 // For eg. "/path/foo%2Fbar/to" will match the path "/path/{var}/to".
-// This behavior has the drawback of needing to match routes against
-// r.RequestURI instead of r.URL.Path. Any modifications (such as http.StripPrefix)
-// to r.URL.Path will not affect routing when this flag is on and thus may
-// induce unintended behavior.
 //
 // If not called, the router will match the unencoded path to the routes.
 // For eg. "/path/foo%2Fbar/to" will match the path "/path/foo/bar/to"