fix(deps): update module github.com/gorilla/mux to v1.8.1

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

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

@@ -22,10 +22,10 @@ type routeRegexpOptions struct {
 type regexpType int
 
 const (
-	regexpTypePath   regexpType = 0
-	regexpTypeHost   regexpType = 1
-	regexpTypePrefix regexpType = 2
-	regexpTypeQuery  regexpType = 3
+	regexpTypePath regexpType = iota
+	regexpTypeHost
+	regexpTypePrefix
+	regexpTypeQuery
 )
 
 // newRouteRegexp parses a route template and returns a routeRegexp,
@@ -195,7 +195,7 @@ func (r *routeRegexp) Match(req *http.Request, match *RouteMatch) bool {
 
 // url builds a URL part using the given values.
 func (r *routeRegexp) url(values map[string]string) (string, error) {
-	urlValues := make([]interface{}, len(r.varsN), len(r.varsN))
+	urlValues := make([]interface{}, len(r.varsN))
 	for k, v := range r.varsN {
 		value, ok := values[v]
 		if !ok {