hi, i think our epoch parsing is not working properly.

if we try to run test_epoch_seconds it would work but if we try changing the timezone to something like env::set_var("TZ", "EST") it would fail. it shouldn't be doing that right? because epoch's should be same even if we change the timezone.

i think it is happening because we are treating NaiveDateTime returned by from_timestamp_opt (which is in UTC) as local time in naive_dt_to_fixed_offset and i think we could fix it by treating it as UTC

if you guys think i'm right can i put together a pr with the necessary changes