One more date fix

Thing is, previously DDay contained only date and '%H:%M:%S' resulted
in an empty string so the whole date was '2021-01-01T::' which is wrong.

src/OpenAlex/Types.hs

@@ -82,8 +82,10 @@ parseTimeE :: (MonadFail m, DTF.ParseTime t) => Text -> Text -> m t
 parseTimeE fmt s = case (DTF.parseTimeM True DTF.defaultTimeLocale (T.unpack fmt) (T.unpack s)) of
   Nothing -> fail $ "Cannot parse date with format " <> T.unpack fmt
   Just  p -> pure p
+
+-- | Convert to ISO text format
 showDate :: Date -> Text
-showDate (DDay day) = T.pack $ DTF.formatTime DTF.defaultTimeLocale "%Y-%m-%dT%H:%M:%S" day
+showDate (DDay day) = T.pack $ DTF.formatTime DTF.defaultTimeLocale "%Y-%m-%dT00:00:00" day
 showDate (DUTCTime t) = T.pack $ DTF.formatTime DTF.defaultTimeLocale "%Y-%m-%dT%H:%M:%S" t
 
 data Date = DDay Day | DUTCTime UTCTime