selenium-webdriver was removed by accident

package.json

@@ -67,6 +67,7 @@
     "postcss": "5.1.0",
     "pre-commit": "1.1.3",
     "sass": "0.5.0",
+    "selenium-webdriver": "2.53.3",
     "tap-spec": "4.1.1",
     "tape": "4.6.3",
     "uppy-server": "0.0.7",