Jiff should use minute precision when comparing offsets after parsing zoned datetimes

[BurntSushi]

This Jiff program:

use jiff::Zoned;

fn main() -> anyhow::Result<()> {
    let zdt: Zoned =
        "1969-12-31T23:15:30-00:44:30[Africa/Monrovia]".parse()?;
    dbg!(&zdt);
    let zdt: Zoned = "1969-12-31T23:15:30-00:45[Africa/Monrovia]".parse()?;
    dbg!(&zdt);

    Ok(())
}

Has this output:

$ cargo -q r
[main.rs:6:5] &zdt = 1969-12-31T23:15:30-00:45[Africa/Monrovia]
Error: parsing "1969-12-31T23:15:30-00:45[Africa/Monrovia]" failed: datetime 1969-12-31T23:15:30 could not resolve to a timestamp since 'reject' conflict resolution was chosen, and because datetime has offset -00:45, but the time zone Africa/Monrovia for the given datetime unambiguously has offset -00:44:30

But it shouldn't error. The reason is that -00:45 as parsed in the second example doesn't match the actual internal offset of -00:44:30.

I realized Jiff had a bug here because of this Temporal issue: tc39/proposal-temporal#3079