Casting date to timestamp fails

[seibs]

Casting from date to timestamp results in TypeError: BigQuery does not support timestamps with timezones.

It looks like Ibis defaults to casting a date to UTC:

>>> ibis.table(ibis.schema([('date', 'date')]))['date'].cast('timestamp')
UnboundTable[r0, name=unbound_table_2]
  date date

cast(date, timestamp('UTC')): timestamp('UTC') = Cast
  date: date = r0.date
  to:
    timestamp('UTC')