chore(deps): update dependency boto3 to v1.16.4 (#4901)
chore(deps): update dependency boto3 to v1.16.4 (#4901)

Co-authored-by: gcf-merge-on-green[bot] <6c7a4de7cdf40496888e303ea3f489f3cc742362@users.noreply.github.com>
GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples