chore: update readme mongodb version

README.md

@@ -42,7 +42,7 @@ Our minimalist "Persona" theme gets you going right away, no coding experience r
 NodeBB requires the following software to be installed:
 
 * A version of Node.js at least 12 or greater ([installation/upgrade instructions](https://github.com/nodesource/distributions))
-* MongoDB, version 2.6 or greater **or** Redis, version 2.8.9 or greater
+* MongoDB, version 3.6 or greater **or** Redis, version 2.8.9 or greater
 * If you are using [clustering](https://docs.nodebb.org/configuring/scaling/) you need Redis installed and configured.
 * nginx, version 1.3.13 or greater (**only if** intending to use nginx to proxy requests to a NodeBB)
 
@@ -81,4 +81,4 @@ Interested in a sublicense agreement for use of NodeBB in a non-free/restrictive
 * [Premium Hosting for NodeBB](http://www.nodebb.org/ "NodeBB")
 * Unofficial IRC community – channel `#nodebb` on Libera.chat
 * [Follow us on Twitter](http://www.twitter.com/NodeBB/ "NodeBB Twitter")
-* [Like us on Facebook](http://www.facebook.com/NodeBB/ "NodeBB Facebook")
+* [Like us on Facebook](http://www.facebook.com/NodeBB/ "NodeBB Facebook")