BUG: tests fail due to missing progress_bar_type argument

[tswast]

Example test failure: https://circleci.com/gh/tswast/pandas-gbq/699?utm_campaign=vcs-integration-link&utm_medium=referral&utm_source=github-build-link

____ TestReadGBQIntegration.test_should_properly_handle_null_timestamp[env] ____

self = <tests.system.test_gbq.TestReadGBQIntegration object at 0x7f6326df4278>
project_id = '****************'

    def test_should_properly_handle_null_timestamp(self, project_id):
        query = "SELECT TIMESTAMP(NULL) AS null_timestamp"
        df = gbq.read_gbq(
            query,
            project_id=project_id,
            credentials=self.credentials,
>           dialect="legacy",
        )

tests/system/test_gbq.py:386: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
pandas_gbq/gbq.py:1034: in read_gbq
    progress_bar_type=progress_bar_type,
pandas_gbq/gbq.py:532: in run_query
    progress_bar_type=progress_bar_type,
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <pandas_gbq.gbq.GbqConnector object at 0x7f6326ddf2e8>
query_job = <google.cloud.bigquery.job.QueryJob object at 0x7f632259d630>
max_results = None, progress_bar_type = 'tqdm'

    def _download_results(
        self, query_job, max_results=None, progress_bar_type=None
    ):
        # No results are desired, so don't bother downloading anything.
        if max_results == 0:
            return None
    
        try:
            bqstorage_client = None
            if max_results is None:
                # Only use the BigQuery Storage API if the full result set is requested.
                bqstorage_client = _make_bqstorage_client(
                    self.use_bqstorage_api, self.credentials
                )
    
            query_job.result()
            # Get the table schema, so that we can list rows.
            destination = self.client.get_table(query_job.destination)
            rows_iter = self.client.list_rows(
                destination, max_results=max_results
            )
    
            schema_fields = [field.to_api_repr() for field in rows_iter.schema]
            nullsafe_dtypes = _bqschema_to_nullsafe_dtypes(schema_fields)
            df = rows_iter.to_dataframe(
                dtypes=nullsafe_dtypes,
                bqstorage_client=bqstorage_client,
>               progress_bar_type=progress_bar_type,
            )
E           TypeError: to_dataframe() got an unexpected keyword argument 'progress_bar_type'

pandas_gbq/gbq.py:562: TypeError

Older versions of the google-cloud-bigquery client don't have a progress_bar_type argument.

Proposed solution:

Detect if the minimum version of google-cloud-bigquery is installed and only then populate the progress_bar_type argument.

Alternatives considered:

• Increment the minimum version of google-cloud-bigquery. As much as possible, we should allow any version of google-cloud-bigquery. The wider we can make the allowed package versions, the less likely it is that people will encounter version conflicts.

[tswast]

On second-thought. progress_bar_type was added in 1.11.0 https://googleapis.dev/python/bigquery/latest/changelog.html in April, 2019. There have been enough releases between now and then that I feel OK about incrementing the minimum version slightly.