add Changelog entry

Author: Amxx

CHANGELOG.md

@@ -5,6 +5,7 @@
  * `Ownable`: add an internal `_transferOwnership(address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/#2568))
  * `AccessControl`: add internal `_grantRole(bytes32,address)` and `_revokeRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/#2568))
  * `AccessControl`: mark `_setupRole(bytes32,address)` as deprecated in favor of `_grantRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/#2568))
+ * `EIP712`: cache `address(this)` to immutable storage to avoid potential issues if a vanila contract is used in an upgradeable context. ([#2852](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/#2852))
 
 ## 4.3.2 (2021-09-14)