**Apache Airflow version**: 2.0.2

**What happened**:

`MongoToS3Operator` failed when running with a single query (not aggregate pipeline):

```sh
Traceback (most recent call last):
  File "/home/airflow//bin/airflow", line 8, in <module>
    sys.exit(main())
  File "/home/airflow//lib/python3.8/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/home/airflow//lib/python3.8/site-packages/airflow/cli/cli_parser.py", line 48, in command
    return func(*args, **kwargs)
  File "/home/airflow//lib/python3.8/site-packages/airflow/utils/cli.py", line 89, in wrapper
    return f(*args, **kwargs)
  File "/home/airflow//lib/python3.8/site-packages/airflow/cli/commands/task_command.py", line 385, in task_test
    ti.run(ignore_task_deps=True, ignore_ti_state=True, test_mode=True)
  File "/home/airflow//lib/python3.8/site-packages/airflow/utils/session.py", line 70, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/airflow//lib/python3.8/site-packages/airflow/models/taskinstance.py", line 1413, in run
    self._run_raw_task(
  File "/home/airflow//lib/python3.8/site-packages/airflow/utils/session.py", line 67, in wrapper
    return func(*args, **kwargs)
  File "/home/airflow//lib/python3.8/site-packages/airflow/models/taskinstance.py", line 1138, in _run_raw_task
    self._prepare_and_execute_task_with_callbacks(context, task)
  File "/home/airflow//lib/python3.8/site-packages/airflow/models/taskinstance.py", line 1311, in _prepare_and_execute_task_with_callbacks
    result = self._execute_task(context, task_copy)
  File "/home/airflow//lib/python3.8/site-packages/airflow/models/taskinstance.py", line 1341, in _execute_task
    result = task_copy.execute(context=context)
  File "/home/airflow//lib/python3.8/site-packages/airflow/providers/amazon/aws/transfers/mongo_to_s3.py", line 116, in execute
    results = MongoHook(self.mongo_conn_id).find(
  File "/home/airflow//lib/python3.8/site-packages/airflow/providers/mongo/hooks/mongo.py", line 144, in find
    return collection.find(query, **kwargs)
  File "/home/airflow//lib/python3.8/site-packages/pymongo/collection.py", line 1523, in find
    return Cursor(self, *args, **kwargs)
TypeError: __init__() got an unexpected keyword argument 'allowDiskUse'
```

**What you expected to happen**:

I expect the data from MongoDB to be exported to a file in S3 with no errors.

**How to reproduce it**:

Run the following operator with a single  `mongo_query` (no aggregate pipeline):

```python
export_to_s3 = MongoToS3Operator(
    task_id='export_to_s3',
    mongo_conn_id=Variable.get('mongo_conn_id'),
    s3_conn_id=Variable.get('aws_conn_id'),
    mongo_collection='my_mongo_collection',
    mongo_query={},
    s3_bucket=Variable.get('s3_bucket'),
    s3_key="my_data.json",
    replace=True,
    dag=dag,
)
```
airflow/providers/amazon/aws/transfers/mongo_to_s3.py
"""Operator meant to move data from mongo via pymongo to s3 via boto.
    :param mongo_conn_id: reference to a specific mongo connection
    :type mongo_conn_id: str
    :param aws_conn_id: reference to a specific S3 connection
    :type aws_conn_id: str
    :param mongo_collection: reference to a specific collection in your mongo db
    :type mongo_collection: str
    :param mongo_query: query to execute. A list including a dict of the query
    :type mongo_query: list
    :param s3_bucket: reference to a specific S3 bucket to store the data
    :type s3_bucket: str
    :param s3_key: in which S3 key the file will be stored
    :type s3_key: str
    :param mongo_db: reference to a specific mongo database
    :type mongo_db: str
    :param replace: whether or not to replace the file in S3 if it previously existed
    :type replace: bool
    :param allow_disk_use: in the case you are retrieving a lot of data, you may have
        to use the disk to save it instead of saving all in the RAM
    :type allow_disk_use: bool
    :param compression: type of compression to use for output file in S3. Currently only gzip is supported.
    :type compression: str
    """
    template_fields = ('s3_bucket', 's3_key', 'mongo_query', 'mongo_collection')
    ui_color = '#589636'
    template_fields_renderers = {"mongo_query": "py"}
    
    def __init__(