Drop puppet, update openvox minimum version to 8.19

* drop support for puppet as discussed in [1]
* update openvox minimum version to 8.19.0 as discussed in [2] and [3]

[1] voxpupuli/community-triage#59
[2] voxpupuli/community-triage#60
[3] voxpupuli/modulesync_config#978 (comment)

Author: TheMeier

metadata.json

@@ -57,13 +57,9 @@
     }
   ],
   "requirements": [
-    {
-      "name": "puppet",
-      "version_requirement": ">= 7.0.0 < 9.0.0"
-    },
     {
       "name": "openvox",
-      "version_requirement": ">= 7.0.0 < 9.0.0"
+      "version_requirement": ">= 8.19.0 < 9.0.0"
     }
   ]
 }