Bump eventlet from 0.29.1 to 0.31.0 (#63)

Bumps [eventlet](https://github.com/eventlet/eventlet) from 0.29.1 to 0.31.0.
- [Release notes](https://github.com/eventlet/eventlet/releases)
- [Changelog](https://github.com/eventlet/eventlet/blob/master/NEWS)
- [Commits](eventlet/eventlet@v0.29.1...v0.31.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,7 +1,7 @@
 astroid==2.4.2
 click==7.1.2
 dnspython==1.16.0
-eventlet==0.29.1
+eventlet==0.31.0
 Flask==1.1.2
 Flask-SocketIO==4.3.1
 greenlet==0.4.17