feat(specs/bridges.md): Sherlock correction

Closing: DEVRL-846

As per https://github.com/sherlock-audit/2023-01-optimism-judging/blob/b7921698c1c537714c5f2021aa46ce0a1935ba39/1-specs-findings/1-processed/1-true/bridge-interface/208.md#L1

specs/bridges.md

@@ -35,7 +35,7 @@ interface StandardBridge {
     function finalizeBridgeERC20(address _localToken, address _remoteToken, address _from, address _to, uint256 _amount, bytes memory _extraData) external;
     function finalizeBridgeETH(address _from, address _to, uint256 _amount, bytes memory _extraData) payable external;
     function messenger() view external returns (address);
-    function otherBridge() view external returns (address);
+    function OTHER_BRIDGE() view external returns (address);
 }
 ```