Bump gunicorn in /test/integration/test_app/frontend (#792)

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 19.9.0 to 23.0.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](benoitc/gunicorn@19.9.0...23.0.0)

---
updated-dependencies:
- dependency-name: gunicorn
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Joe Rice <[email protected]>

Author: dependabot[bot]

test/integration/test_app/frontend/requirements.txt

@@ -1,4 +1,4 @@
 flask
 requests
 aws-xray-sdk
-gunicorn==19.9.0
+gunicorn==23.0.0