Update metadata and dependencies

metadata.json

@@ -8,7 +8,7 @@
   "project_page": "https://git.icinga.com/icinga-testing/puppet-icinga2_notificationtest",
   "issues_url": "https://git.icinga.com/icinga-testing/puppet-icinga2_notificationtest/issues",
   "dependencies": [
-    {"name":"puppetlabs-stdlib","version_requirement":">= 1.0.0"}
+    {"name":"puppetlabs-stdlib","version_requirement":">= 1.0.0 < 5.0.0"}
   ],
   "operatingsystem_support": [
     {