Composer: use gopay-api v2.5.4

Author: f3l1x

Diff for: composer.json

@@ -24,7 +24,7 @@
   ],
   "require": {
     "php": ">=5.6",
-    "markette/gopay-api": "^2.5.3",
+    "markette/gopay-api": "^2.5.4",
     "nette/forms": "~2.3.0|~2.4.0",
     "nette/application": "~2.3.0|~2.4.0",
     "nette/di": "~2.3.0|~2.4.0"