chore(deps): bump gunicorn in /tests/apps/python-flask
chore(deps): bump gunicorn in /tests/apps/python-flask

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 19.9.0 to 20.0.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](https://github.com/benoitc/gunicorn/compare/19.9.0...20.0.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
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