chore: add classifier for python 3.9 (#132)
chore: add classifier for python 3.9 (#132)

added support for python 3.9

Co-authored-by: Anthonios Partheniou <50de7473c4bcd6fb06c46bebfdc91e30df56824a@google.com>
googleapis/python-bigquery-connection,googleapis/python-bigquery-connection