don't send group id when creating a block

Author: toddtreece

src/blocks/AdafruitIO_Block.cpp

@@ -62,8 +62,7 @@ bool AdafruitIO_Block::save()
   url += _dashboard->name;
   url += "/blocks";
 
-  String block_feeds = "[{\"group_id\":\"default\",";
-  block_feeds += "\"feed_id\":\"";
+  String block_feeds = "[{\"feed_id\":\"";
   block_feeds += _feed->name;
   block_feeds += "\"}]";