utilise channel type filtering for channel options

src/structure/interfaces/CommandOption.js

@@ -25,6 +25,10 @@ const Constants = {
         MENTIONABLE: 9,
         NUMBER: 10,
         FLOAT: 10
+    },
+    ChannelTypes: {
+        TEXT_CHANNEL: 0,
+        VOICE_CHANNEL: 3
     }
 };
 
@@ -128,7 +132,8 @@ class CommandOption {
             choices: this.choices,
             options: this.options.map((o) => o.shape),
             min_value: this.minimum,
-            max_value: this.maximum
+            max_value: this.maximum,
+            channel_types: Constants.ChannelTypes[this.type] !== undefined ? [Constants.ChannelTypes[this.type]] : null
         };
     }