ChangeStreamTask does not handle $showExpandedEvents

[nlescure-pictet]

Hi,

I was looking at the source code of the ChangeStreamTask and I realized that when creating the ChangeStreamIterable, the code doesn't set the above mentioned flag. It would have to be added to the ChangeStreamOptions.builder() as well.
At the moment, it is therefore impossible to listen to the following types of events: createIndexes, dropIndexes, modify, create, shardCollection, reshardCollection, refineCollectionShardKey (because the flag is false by default.)

Cheers.