updateOrCreate method
Updates data on the document if it exists. Data will be merged with any existing document data.
If no document exists, a new document will be created
The value returned is the value passed in, a read is not performed
Implementation
@override
Future<T> updateOrCreate({
required DocumentId docId,
required T value,
}) async {
await ref.doc(docId.docId).set(value, SetOptions(merge: true));
return value;
}