Update pragma to 0.8.20 (#4489)

Co-authored-by: Francisco Giordano <fg@frang.io>
Co-authored-by: ernestognw <ernestognw@gmail.com>

contracts/mocks/DummyImplementation.sol

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.8.19;
+pragma solidity ^0.8.20;
 
 import {ERC1967Utils} from "../proxy/ERC1967/ERC1967Utils.sol";
 import {StorageSlot} from "../utils/StorageSlot.sol";