[Snyk] Security upgrade gunicorn from 20.0.4 to 21.2.0

[Redwoodtj]

Snyk has created this PR to fix 1 vulnerabilities in the pip dependencies of this project.

Snyk changed the following file(s):

• surface/requirements_prod.txt

---

Important

• Check the changes in this PR to ensure they won't cause issues with your project.
• Max score is 1000. Note that the real score may have changed since the PR was raised.
• This PR was automatically created by Snyk using the credentials of a real user.
• Some vulnerabilities couldn't be fully fixed and so Snyk will still find them when the project is tested again. This may be because the vulnerability existed within more than one direct dependency, but not all of the affected dependencies could be upgraded.

---

Note: You are seeing this because you or someone else with access to this repository has authorized Snyk to open fix PRs.

For more information:
🧐 View latest project report
📜 Customise PR templates
🛠 Adjust project settings
📚 Read about Snyk's upgrade logic

---

Learn how to fix vulnerabilities with free interactive lessons:

🦉 Learn about vulnerability in an interactive lesson of Snyk Learn.

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.