Update security.rst

Co-authored-by: Christian Flothmann <[email protected]>

Author: ThomasLandauer

security.rst

@@ -555,7 +555,7 @@ will be able to authenticate (e.g. login form, API token, etc).
             // the order in which firewalls are defined is very important, as the
             // request will be handled by the first firewall whose pattern matches
             $security->firewall('dev')
-                ->pattern('^/_profiler|_wdt|assets|build/') // `assets` is for AssetMapper; `build` is for Webpack Encore
+                ->pattern('^/(_profiler|_wdt|assets|build)/') // `assets` is for AssetMapper; `build` is for Webpack Encore
                 ->security(false)
             ;