Trigger support for withConverter

Not sure if you accept Feature Requests, but I'll make it brief:

Would be nice if the `onCreate`, `onWrite`, `onUpdate` and `onDelete` triggers had support for `withConverter`:

Example:
```typescript
firestore
.document(`businesses/{businessId}`)
.withConverter(new BusinessConverter())
.onWrite(async (change, context) => {
const business: Business = change.after.data()
})
```

Thanks

ref: https://github.com/googleapis/nodejs-firestore/issues/1449