Error with `PluginFunc` type for UTC

**Describe the bug**
We are using DayJs with Deno and are getting the following error:


At the moment, we are having to assert the type to avoid this error as follows:
```ts
dayjs.extend(utc as PluginFunc);
```

**Expected behavior**
No type error is given.

**Information**
- Day.js Version [e.g. v1.11.10]
- Deno 1.37.1

Reproduce the Deno usage with the UTC plugin and inspect the PluginFunc type used by dayjs.extend. Confirm the type mismatch and identify the relevant plugin typing entry point; done means dayjs.extend(utc) type-checks without a type assertion.

Written by the indexing model from the issue text.