Add RSS channel to support section in composer schema (closes #5073)

doc/04-schema.md

@@ -238,6 +238,7 @@ Support information includes the following:
 * **irc:** IRC channel for support, as irc://server/channel.
 * **source:** URL to browse or download the sources.
 * **docs:** URL to the documentation.
+* **rss:** URL to the RSS feed.
 
 An example:
 

res/composer-schema.json

@@ -465,6 +465,11 @@
                     "type": "string",
                     "description": "URL to the documentation.",
                     "format": "uri"
+                },
+                "rss": {
+                    "type": "string",
+                    "description": "URL to the RSS feed.",
+                    "format": "uri"
                 }
             }
         },