Move chai extension types out of @0x/typescript-typings

packages/dev-utils/src/chai_setup.ts

@@ -1,3 +1,4 @@
+import { RevertError } from '@0x/utils';
 import * as chai from 'chai';
 import chaiAsPromised = require('chai-as-promised');
 import ChaiBigNumber = require('chai-bignumber');
@@ -5,6 +6,14 @@ import * as dirtyChai from 'dirty-chai';
 
 import { revertErrorHelper } from './chai_revert_error';
 
+declare global {
+    namespace Chai {
+        export interface Assertion {
+            revertWith: (expected: string | RevertError) => Promise<void>;
+        }
+    }
+}
+
 export const chaiSetup = {
     configure(): void {
         chai.config.includeStack = true;