Upstream staging module released 2.2.0. Allow using it.

metadata.json

@@ -49,6 +49,6 @@
   "dependencies": [
     {"name":"puppetlabs/stdlib","version_requirement":">= 3.13.1 < 5.0.0"},
     {"name":"puppetlabs/apt","version_requirement":">= 1.8.0 < 3.0.0"},
-    {"name":"puppet/staging","version_requirement":">= 0.3.1 < 2.0.0"}
+    {"name":"puppet/staging","version_requirement":">= 0.3.1 < 3.0.0"}
   ]
 }