Bump version to 4.0.0 (#20636)

CHANGELOG.md

@@ -3,7 +3,7 @@ Changelog
 
 All notable changes to this project will be documented in this file.
 
-## [Unreleased]
+## [4.0.0] - 2022-11-14
 
 Some of the features in this release have been funded through the [NGI0 Discovery](https://nlnet.nl/discovery) Fund, a fund established by [NLnet](https://nlnet.nl/) with financial support from the European Commission's [Next Generation Internet](https://ngi.eu/) programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 825322.
 
@@ -196,6 +196,10 @@ Some of the features in this release have been funded through the [NGI0 Discover
 ### Security
 
 - Fix being able to spoof link verification ([Gargron](https://github.com/mastodon/mastodon/pull/20217))
+- Fix emoji substitution not applying only to text nodes in backend code ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/20641))
+- Fix emoji substitution not applying only to text nodes in web UI ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/20640))
+- Fix rate limiting for paths with formats ([Gargron](https://github.com/mastodon/mastodon/pull/20675))
+- Fix out-of-bound reads in blurhash transcoder ([delroth](https://github.com/mastodon/mastodon/pull/20388))
 
 ## [3.5.3] - 2022-05-26
 ### Added

lib/mastodon/version.rb

@@ -17,7 +17,7 @@ module Mastodon
     end
 
     def flags
-      'rc4'
+      ''
     end
 
     def suffix