Merge #64

64: Update eventlet to 0.28.0 r=duckinator a=pyup-bot


This PR updates [eventlet](https://pypi.org/project/eventlet) from **0.27.0** to **0.28.0**.



<details>
  <summary>Changelog</summary>
  
  
   ### 0.28.0
   ```
   ======
* Always remove the right listener from the hub eventlet/eventlet#645
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/eventlet
  - Changelog: https://pyup.io/changelogs/eventlet/
  - Homepage: http://eventlet.net
</details>



Co-authored-by: pyup-bot <github-bot@pyup.io>

requirements.txt

@@ -1,6 +1,6 @@
 cherrypy==18.6.0
 jinja2==2.11.2
 gunicorn==20.0.4
-eventlet==0.27.0
+eventlet==0.28.0
 pillow==7.2.0
 elasticsearch>=7.7.0,<8.0.0