Don't use sinon.useFakeTimers

Author: papandreou

bootstrap-unexpected-markdown.js

@@ -4,8 +4,3 @@ unexpected = require('unexpected').clone();
 express = require('express');
 unexpected.output.preferredWidth = 80;
 unexpected.installPlugin(require('./lib/unexpectedExpress'));
-
-require('sinon').useFakeTimers({
-  now: 1457823364125,
-  toFake: ['Date'],
-});

package.json

@@ -53,7 +53,6 @@
     "nyc": "^15.0.0",
     "offline-github-changelog": "^2.0.0",
     "prettier": "~2.1.0",
-    "sinon": "^9.0.0",
     "unexpected": "^12.0.0",
     "unexpected-documentation-site-generator": "^6.0.0",
     "unexpected-markdown": "^5.0.0",