fix: fix usdb l2 bridge signature (#554)

contracts/Blast_SpokePool.sol

@@ -32,6 +32,17 @@ interface IBlast {
     function claimMaxGas(address contractAddress, address recipientOfGas) external returns (uint256);
 }
 
+interface IUSDBL2Bridge {
+    function bridgeERC20To(
+        address _localToken,
+        address _remoteToken,
+        address _to,
+        uint256 _amount,
+        uint32 _minGasLimit,
+        bytes calldata _extraData
+    ) external;
+}
+
 /**
  * @notice Blast Spoke pool.
  */
@@ -130,7 +141,7 @@ contract Blast_SpokePool is Ovm_SpokePool {
         }
         // If the token is USDB then use the L2BlastBridge
         if (l2TokenAddress == USDB) {
-            IL2ERC20Bridge(L2_BLAST_BRIDGE).bridgeERC20To(
+            IUSDBL2Bridge(L2_BLAST_BRIDGE).bridgeERC20To(
                 l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
                 L1_USDB,
                 hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.