Fix version

Author: cretueusebiu

composer.json

@@ -15,7 +15,7 @@
         "php": ">=5.6.4",
         "illuminate/notifications": "5.3.*",
         "illuminate/support": "5.1.*|5.2.*|5.3.*",
-        "minishlink/web-push": "^1.1"
+        "minishlink/web-push": "1.1.*"
     },
     "require-dev": {
         "mockery/mockery": "^0.9.5",