Manipulate with utc0 time is wrong!

**Describe the bug**

```js
dayjs('2022-01-23').utcOffset(0, true).format()
// print: 2022-01-23T00:00:00Z

dayjs('2022-01-23').utcOffset(0, true).add(1, 'minute').format()
// print 2022-01-22T16:01:00Z
// !!!

dayjs('2022-01-23').utcOffset(1, true).format()
// print 2022-01-23T00:00:00+01:00

dayjs('2022-01-23').utcOffset(1, true).add(1, 'minute').format()
// print 2022-01-23T00:01:00+01:00
```

**Expected behavior**

```js
dayjs('2022-01-23').utcOffset(0, true).add(1, 'minute').format()
// should print:
// print: 2022-01-23T00:01:00Z
```

**Information**
- Day.js Version 1.10.7
- OS: MacOs
- Browser chrome 96.0.4664.93
- Time zone: GMT+0800

Start by reproducing the utcOffset(0, true).add(1, 'minute').format() example from the issue, then trace the utcOffset and add entry points in Day.js. Done means the UTC offset-zero case formats as 2022-01-23T00:01:00Z without changing the behavior shown for offset 1.

Written by the indexing model from the issue text.