Fix incorrect gain flag type.

quartical/gains/feed_flip/__init__.py

@@ -42,6 +42,6 @@ def init_term(self, term_spec, ref_ant, ms_kwargs, term_kwargs, meta=None):
                 "Feed flip unsupported for less than four correlations"
             )
 
-        gain_flags = np.zeros(gains.shape[:-1], dtype=bool)
+        gain_flags = np.zeros(gains.shape[:-1], dtype=np.int8)
 
         return gains, gain_flags