Add ER_UNKNOWN_PREPARED_STATEMENT_HANDLER to default_codes (#205)

Author: francesco995

lib/myxql/protocol/server_error_codes.ex

@@ -22,6 +22,7 @@ defmodule MyXQL.Protocol.ServerErrorCodes do
     {1062, :ER_DUP_ENTRY},
     {1146, :ER_NO_SUCH_TABLE},
     {1207, :ER_READ_ONLY_TRANSACTION},
+    {1243, :ER_UNKNOWN_PREPARED_STATEMENT_HANDLER},
     {1295, :ER_UNSUPPORTED_PS},
     {1421, :ER_STMT_HAS_NO_OPEN_CURSOR},
     {1451, :ER_ROW_IS_REFERENCED_2},