refactor: use Ownable2Step instead of Ownable

This has been discussed in #7 and be further explored in OpenZeppelin/openzeppelin-contracts#3620

Closes #7

.gas-snapshot

@@ -1,7 +1,7 @@
-AddEntryTest:test_AddEntry() (gas: 44369)
-AddEntryTest:test_RevertWhen_EntryAlreadyExists() (gas: 42598)
-AddEntryTest:test_RevertWhen_InvalidAddress() (gas: 25087)
-AddEntryTest:test_RevertWhen_SenderIsNotTokenDeployer() (gas: 14804)
+AddEntryTest:test_AddEntry() (gas: 44392)
+AddEntryTest:test_RevertWhen_EntryAlreadyExists() (gas: 42644)
+AddEntryTest:test_RevertWhen_InvalidAddress() (gas: 25133)
+AddEntryTest:test_RevertWhen_SenderIsNotTokenDeployer() (gas: 14827)
 CollectibleV1Test:test_Deployment() (gas: 38626)
 CommunityERC20Test:test_Deployment() (gas: 29720)
 CommunityTokenDeployerTest:test_Deployment() (gas: 14805)
@@ -16,18 +16,18 @@ CreateTest:test_RevertWhen_SenderIsNotTokenDeployer() (gas: 16421)
 CreateTest:test_RevertWhen_SenderIsNotTokenDeployer() (gas: 16524)
 DeployContracts:test() (gas: 120)
 DeployOwnerAndMasterToken:test() (gas: 120)
-DeployTest:test_Deploy() (gas: 4840232)
+DeployTest:test_Deploy() (gas: 4840322)
 DeployTest:test_Deployment() (gas: 14925)
-DeployTest:test_RevertWhen_AlreadyDeployed() (gas: 4836115)
-DeployTest:test_RevertWhen_DeploymentSignatureExpired() (gas: 53642)
-DeployTest:test_RevertWhen_InvalidCommunityAddress() (gas: 51341)
-DeployTest:test_RevertWhen_InvalidDeployerAddress() (gas: 55329)
-DeployTest:test_RevertWhen_InvalidDeploymentSignature() (gas: 65663)
-DeployTest:test_RevertWhen_InvalidSignerPublicKey() (gas: 53435)
-DeployTest:test_RevertWhen_InvalidTokenMetadata() (gas: 2639807)
+DeployTest:test_RevertWhen_AlreadyDeployed() (gas: 4836205)
+DeployTest:test_RevertWhen_DeploymentSignatureExpired() (gas: 53709)
+DeployTest:test_RevertWhen_InvalidCommunityAddress() (gas: 51408)
+DeployTest:test_RevertWhen_InvalidDeployerAddress() (gas: 55396)
+DeployTest:test_RevertWhen_InvalidDeploymentSignature() (gas: 65730)
+DeployTest:test_RevertWhen_InvalidSignerPublicKey() (gas: 53502)
+DeployTest:test_RevertWhen_InvalidTokenMetadata() (gas: 2639874)
 DeploymentTest:test_Deployment() (gas: 14671)
 DeploymentTest:test_Deployment() (gas: 14671)
-DeploymentTest:test_Deployment() (gas: 17250)
+DeploymentTest:test_Deployment() (gas: 17295)
 GetEntryTest:test_ReturnZeroAddressIfEntryDoesNotExist() (gas: 11906)
 MintToTest:test_Deployment() (gas: 29742)
 MintToTest:test_Deployment() (gas: 38626)
@@ -44,17 +44,17 @@ RemoteBurnTest:test_Deployment() (gas: 85482)
 RemoteBurnTest:test_RemoteBurn() (gas: 455285)
 RemoteBurnTest:test_RevertWhen_RemoteBurn() (gas: 19499)
 RemoteBurnTest:test_RevertWhen_SenderIsNotOwner() (gas: 25211)
-SetCommunityTokenDeployerAddressTest:test_RevertWhen_InvalidTokenDeployerAddress() (gas: 12963)
-SetCommunityTokenDeployerAddressTest:test_RevertWhen_SenderIsNotOwner() (gas: 12504)
-SetCommunityTokenDeployerAddressTest:test_SetCommunityTokenDeployerAddress() (gas: 22807)
+SetCommunityTokenDeployerAddressTest:test_RevertWhen_InvalidTokenDeployerAddress() (gas: 12941)
+SetCommunityTokenDeployerAddressTest:test_RevertWhen_SenderIsNotOwner() (gas: 12482)
+SetCommunityTokenDeployerAddressTest:test_SetCommunityTokenDeployerAddress() (gas: 22808)
 SetDeploymentRegistryAddressTest:test_Deployment() (gas: 14827)
 SetDeploymentRegistryAddressTest:test_RevertWhen_InvalidDeploymentRegistryAddress() (gas: 13014)
 SetDeploymentRegistryAddressTest:test_RevertWhen_SenderIsNotOwner() (gas: 12508)
-SetDeploymentRegistryAddressTest:test_SetDeploymentRegistryAddress() (gas: 22903)
+SetDeploymentRegistryAddressTest:test_SetDeploymentRegistryAddress() (gas: 22881)
 SetMasterTokenFactoryAddressTest:test_Deployment() (gas: 14805)
 SetMasterTokenFactoryAddressTest:test_RevertWhen_InvalidTokenFactoryAddress() (gas: 13014)
 SetMasterTokenFactoryAddressTest:test_RevertWhen_SenderIsNotOwner() (gas: 12487)
-SetMasterTokenFactoryAddressTest:test_SetOwnerTokenFactoryAddress() (gas: 22861)
+SetMasterTokenFactoryAddressTest:test_SetOwnerTokenFactoryAddress() (gas: 22883)
 SetMaxSupplyTest:test_Deployment() (gas: 29720)
 SetMaxSupplyTest:test_Deployment() (gas: 85482)
 SetMaxSupplyTest:test_RevertWhen_CalledBecauseMaxSupplyIsLocked() (gas: 16521)

contracts/CommunityOwnerTokenRegistry.sol

@@ -2,7 +2,7 @@
 
 pragma solidity ^0.8.17;
 
-import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
+import { Ownable2Step } from "@openzeppelin/contracts/access/Ownable2Step.sol";
 import { IAddressRegistry } from "./interfaces/IAddressRegistry.sol";
 import { OwnerToken } from "./tokens/OwnerToken.sol";
 
@@ -24,7 +24,7 @@ import { OwnerToken } from "./tokens/OwnerToken.sol";
  * registry contract.
  * @dev Only `tokenDeployer` can add entries to the registry.
  */
-contract CommunityOwnerTokenRegistry is IAddressRegistry, Ownable {
+contract CommunityOwnerTokenRegistry is IAddressRegistry, Ownable2Step {
     error CommunityOwnerTokenRegistry_NotAuthorized();
     error CommunityOwnerTokenRegistry_EntryAlreadyExists();
     error CommunityOwnerTokenRegistry_InvalidAddress();

contracts/CommunityTokenDeployer.sol

@@ -2,7 +2,7 @@
 
 pragma solidity ^0.8.17;
 
-import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
+import { Ownable2Step } from "@openzeppelin/contracts/access/Ownable2Step.sol";
 import { ECDSA } from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
 import { EIP712 } from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";
 import { ITokenFactory } from "./interfaces/ITokenFactory.sol";
@@ -39,7 +39,7 @@ import { IAddressRegistry } from "./interfaces/IAddressRegistry.sol";
  * @dev The `CommunityOwnerTokenFactory` address can be changed by the owner of this contract.
  * @dev The `CommunityMasterTokenFactory` address can be changed by the owner of this contract.
  */
-contract CommunityTokenDeployer is EIP712("CommunityTokenDeployer", "1"), Ownable {
+contract CommunityTokenDeployer is EIP712("CommunityTokenDeployer", "1"), Ownable2Step {
     using ECDSA for bytes32;
 
     error CommunityTokenDeployer_InvalidDeploymentRegistryAddress();

contracts/factories/BaseTokenFactory.sol

@@ -2,7 +2,7 @@
 pragma solidity ^0.8.17;
 
 import { ITokenFactory } from "../interfaces/ITokenFactory.sol";
-import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
+import { Ownable2Step } from "@openzeppelin/contracts/access/Ownable2Step.sol";
 
 /**
  * @title BaseTokenFactory contract
@@ -15,7 +15,7 @@ import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
  *
  * @dev Other factory contract inherit from this contract.
  */
-abstract contract BaseTokenFactory is ITokenFactory, Ownable {
+abstract contract BaseTokenFactory is ITokenFactory, Ownable2Step {
     error BaseTokenFactory_InvalidTokenDeployerAddress();
     error BaseTokenFactory_NotAuthorized();
     error BaseTokenFactory_InvalidTokenMetadata();