Add gaps and _disableInitializers call in Bridge.sol

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -1,8 +1,8 @@
 name: Bug Report
 description: File a bug report
 labels: ['bug']
-assignees:
-  - Arvolear
+assignees: 
+  - arvolear
 body:
   - type: markdown
     attributes:

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -1,8 +1,8 @@
 name: Feature request
 description: Suggest a new feature
 labels: ['feature']
-assignees:
-  - Arvolear
+assignees: 
+  - arvolear
 body:
   - type: textarea
     id: feature-description

.github/actions/setup/action.yml

@@ -1,14 +1,12 @@
 name: setup
 
-description: setup
-
 runs:
   using: composite
   steps:
     - name: Setup node
       uses: actions/setup-node@v3
       with:
-        node-version: "16.18.x"
+        node-version: "20.18.x"
         cache: npm
     - name: Install packages
       run: npm install

contracts/bridge/Bridge.sol

@@ -26,6 +26,13 @@ contract Bridge is
     ERC1155Handler,
     NativeHandler
 {
+    /**
+     * @dev Disables the ability to call initializers.
+     */
+    constructor() {
+        _disableInitializers();
+    }
+
     function __Bridge_init(
         address[] calldata signers_,
         uint256 signaturesThreshold_

contracts/handlers/ERC1155Handler.sol

@@ -10,6 +10,13 @@ import {IERC1155MintableBurnable} from "../interfaces/tokens/IERC1155MintableBur
  * @title ERC1155Handler
  */
 abstract contract ERC1155Handler is IERC1155Handler, ERC1155Holder {
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[50] private __gap;
+
     /**
      * @inheritdoc IERC1155Handler
      */

contracts/handlers/ERC20Handler.sol

@@ -13,6 +13,13 @@ import {IERC20MintableBurnable} from "../interfaces/tokens/IERC20MintableBurnabl
 abstract contract ERC20Handler is IERC20Handler {
     using SafeERC20 for IERC20MintableBurnable;
 
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[50] private __gap;
+
     /**
      * @inheritdoc IERC20Handler
      */

contracts/handlers/ERC721Handler.sol

@@ -10,6 +10,13 @@ import {IERC721MintableBurnable} from "../interfaces/tokens/IERC721MintableBurna
  * @title ERC721Handler
  */
 abstract contract ERC721Handler is IERC721Handler, ERC721Holder {
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[50] private __gap;
+
     /**
      * @inheritdoc IERC721Handler
      */

contracts/handlers/NativeHandler.sol

@@ -7,6 +7,13 @@ import {INativeHandler} from "../interfaces/handlers/INativeHandler.sol";
  * @title NativeHandler
  */
 abstract contract NativeHandler is INativeHandler {
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[50] private __gap;
+
     receive() external payable {}
 
     /**

contracts/utils/Hashes.sol

@@ -4,6 +4,13 @@ pragma solidity ^0.8.9;
 abstract contract Hashes {
     mapping(bytes32 => bool) public usedHashes; // keccak256(txHash . txNonce) => is used
 
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[49] private __gap;
+
     function containsHash(bytes32 txHash_, uint256 txNonce_) external view returns (bool) {
         bytes32 nonceHash_ = keccak256(abi.encodePacked(txHash_, txNonce_));
 

contracts/utils/Signers.sol

@@ -13,6 +13,13 @@ abstract contract Signers is OwnableUpgradeable {
 
     EnumerableSet.AddressSet internal _signers;
 
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
+     */
+    uint256[48] private __gap;
+
     function __Signers_init(
         address[] calldata signers_,
         uint256 signaturesThreshold_