Update changelog to list beta bugfix separately

(cherry picked from commit 5aab6ff81b)

CHANGELOG.md

@@ -19,7 +19,10 @@
  * `ERC777`: Optimize the gas costs of the constructor. ([#2551](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2551))
  * `ERC721URIStorage`: Add a new extension that implements the `_setTokenURI` behavior as it was available in 3.4.0. ([#2555](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2555))
  * `AccessControl`: Added ERC165 interface detection. ([#2562](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2562))
- * `AccessControlEnumerable`: Fixed `renounceRole` not updated underlying set. ([#2572](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2572))
+
+### Bug fixes for beta releases
+
+ * `AccessControlEnumerable`: Fixed `renounceRole` not updating enumerable set of addresses for a role. ([#2572](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2572))
 
 ### How to upgrade from 3.x