chore(bigquery): use 3.6 for blacken session (#10012)
chore(bigquery): use 3.6 for blacken session (#10012)

* [CHANGE ME] Re-generated bigquery to pick up changes in the API or client library generator.

* chore: use 3.6 for blacken session

* chore: blacken

* chore: add comment about why 3.6 is used

* chore: revert changes to metadata

Co-authored-by: Bu Sun Kim <e20aa14702d7e04a52a901b5515eeecef97a5b5f@users.noreply.github.com>

googleapis/google-cloud-python,googleapis/google-cloud-python,GoogleCloudPlatform/gcloud-python,tswast/google-cloud-python,tswast/google-cloud-python,GoogleCloudPlatform/gcloud-python,tswast/google-cloud-python