Merge pull request #606 from puppetlabs/CAT-2152

(CAT-2152) Add support for Centos9

Author: skyamgarp

metadata.json

@@ -30,7 +30,8 @@
       "operatingsystem": "CentOS",
       "operatingsystemrelease": [
         "7",
-        "8"
+        "8",
+        "9"
       ]
     },
     {