Calling `toISOString` on a Duration object does not return weeks

[behdi]

Describe the bug
There's a weird behavior when it comes to getting an ISO duration string from the dayjs's duration object. For example:

dayjs.duration({ year:1, week: 2 }).toISOString(); // 'P1Y14D'
dayjs.duration('P2Y3W5D').toISOString(); // 'P2Y26D'

Expected behavior
It'd be really great if weeks weren't converted to days. So we'd get these in the output:

dayjs.duration({ year:1, week: 2 }).toISOString(); // 'P1Y2W'
dayjs.duration('P2Y3W5D').toISOString(); // 'P2Y3W5D'

Information

• Day.js Version: v1.11.8
• OS: Linux
• Browser: Brave v 1.77.97
• Time zone: GMT+3:30