Use Python 3.9 for run/django (#5332)
Use Python 3.9 for run/django (#5332)

Co-authored-by: Ace Nassri <66a75941ededf131c26806c52c2b5e1fb48aad03@google.com>
GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples