Drop support of Puppet 4 and 5 (EOL)

Author: smortex

metadata.json

@@ -77,7 +77,7 @@
   "requirements": [
     {
       "name": "puppet",
-      "version_requirement": ">= 4.10.0 < 7.0.0"
+      "version_requirement": ">= 6.1.0 < 7.0.0"
     }
   ]
 }