fix otc field in ws equity agg (#274)

Author: morningvera

polygon/websocket/models/models.py

@@ -39,7 +39,7 @@ def from_dict(d):
             d.get("z", None),
             d.get("s", None),
             d.get("e", None),
-            d.get("o", None),
+            d.get("otc", None),
         )