Bump gevent from 20.5.2 to 23.9.0

Bumps [gevent](https://github.com/gevent/gevent) from 20.5.2 to 23.9.0.
- [Release notes](https://github.com/gevent/gevent/releases)
- [Changelog](https://github.com/gevent/gevent/blob/master/docs/changelog_pre.rst)
- [Commits](gevent/gevent@20.5.2...23.9.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -12,7 +12,7 @@ Eel==0.11.0
 Equation==1.2.1
 Flask==2.1.2
 future==0.18.3
-gevent==20.5.2
+gevent==23.9.0
 gevent-websocket==0.10.1
 greenlet==0.4.15
 gunicorn==20.0.4