require.undef() interface does not include recursive argument

**Bug**

The interface definition of `require.undef()` does not include the second optional argument of `recursive`.

Package Version: beta1

**Code**

```typescript
require.undef('some/mid', true); // throws TypeScript error
```

**Expected behavior:**

Works without issue.

**Actual behavior:**

Complains that supplied arguments do not match the signature.
