Updated image on gravatar, not seeing it update on site

[sam (Sam Saffron)]

This is meant to correct the avatar right away looking at the code:

https://github.com/discourse/discourse/blob/ce00da3bcd29f1555dcfcfe241e968efbd249944/app/controllers/user_avatars_controller.rb#L7-L14

@kris.kotlarek can you repro this issue and fix?

Gravatar could very possibly be at fault here, caching something on their end for too long.