fix bad module name

Author: polymorpher

code/extensions/contracts.js

@@ -6,7 +6,7 @@ const DomainManager = require('../build/contracts/DomainManager.json')
 const SpendingManager = require('../build/contracts/SpendingManager.json')
 const CoreManager = require('../build/contracts/CoreManager.json')
 const Executor = require('../build/contracts/Executor.json')
-const Staking = require('../build/contracts/staking.json')
+const Staking = require('../build/contracts/Staking.json')
 const ONEWalletFactory = require('../build/contracts/ONEWalletFactory.json')
 const ONEWalletFactoryHelper = require('../build/contracts/ONEWalletFactoryHelper.json')
 const ONEWalletCodeHelper = require('../build/contracts/ONEWalletCodeHelper.json')