dfr get-second for dataframe

Gets second from date.

Signature

> dfr get-second

Examples

Returns second from a date

> let dt = ('2020-08-04T16:39:18+00:00' | into datetime -z 'UTC');
    let df = ([$dt $dt] | dfr into-df);
    $df | dfr get-second
╭───┬────╮
│ # │ 0  │
├───┼────┤
│ 0 │ 18 │
│ 1 │ 18 │
╰───┴────╯