Call out Redict compatibility

Redis is [no longer open source](redis/redis#13157), [Redict](https://redict.io/) is a still-open-source fork that is essentially what redis was - see https://andrewkelley.me/post/redis-renamed-to-redict.html

This just updates the readme to clarify that we work with both.

We will probably want to include redict in our automated testing eventually, although they are essentially identical for the moment.

readme.md

@@ -11,7 +11,8 @@
 
 <div align="center">
 
-A [`redis`](https://github.com/redis/redis) store for the
+A [`redict`](https://redict.io/) & [`redis`](https://github.com/redis/redis)
+store for the
 [`express-rate-limit`](https://github.com/nfriedly/express-rate-limit)
 middleware.
 
@@ -148,7 +149,7 @@ below:
 
 #### `prefix`
 
-The text to prepend to the key in Redis.
+The text to prepend to the key in Redict/Redis.
 
 Defaults to `rl:`.