*`AccessControl`: add a virtual `_checkRole(bytes32)` function that can be overriden to alter the `onlyRole` modifier behavior. ([#3137](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3137))
*`EnumerableMap`: add new `AddressToUintMap` map type. ([#3150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3150))