fix(sqlalchemy-bigquery): Drop support for Python 3.8 and 3.9#16956

parthea merged 11 commits intomaingoogleapis/google-cloud-python:mainfrom

feat/drop-python-3.7-3.9-sqlalchemy-bigquerygoogleapis/google-cloud-python:feat/drop-python-3.7-3.9-sqlalchemy-bigqueryCopy head branch name to clipboard