Adding version_added field to metadata field in s3 module

library/cloud/s3

@@ -88,6 +88,8 @@ options:
       - Metadata for PUT operation, as a dictionary of 'key=value' and 'key=value,key=value'.
     required: false
     default: null
+    version_added: "1.6"
+
 requirements: [ "boto" ]
 author: Lester Wade, Ralph Tice
 '''