utcOffset Interface error

I am using utcOffset in TypeScript project, but the interface of utcOffset may be error.
```
dayjs()
.utcOffset(timeZone)
.add(4, 'y')
.format(patten);
```

node_modules/dayjs/index.d.ts utcOffset(): number

Start with node_modules/dayjs/index.d.ts and compare the declared utcOffset interface with the usage shown in the issue. Verify the intended utcOffset call in a TypeScript project and add or update the relevant declaration and test so the interface matches the supported API.

Written by the indexing model from the issue text.