updated version added for source into the docs

system/firewalld.py

@@ -46,6 +46,7 @@ options:
       - 'The source/network you would like to add/remove to/from firewalld'
     required: false
     default: null
+    version_added: "2.0"
   zone:
     description:
       - 'The firewalld zone to add/remove to/from (NOTE: default zone can be configured per system but "public" is default from upstream. Available choices can be extended based on per-system configs, listed here are "out of the box" defaults).'