Update dependencies (#234)

* Bumps pa11y-webservice and client to the new versions requiring node 8+
* Update tests to account for the new URL. Integration tests now include a localhost URL, this updates the tests to reflect that.
* Increase test timeout to avoid travis failing

package.json

@@ -32,8 +32,8 @@
     "express": "^4.16.3",
     "http-headers": "^3.0.1",
     "moment": "^2.22.2",
-    "pa11y-webservice-client-node": "^1.2.1",
-    "pa11y-webservice": "^2.3.1",
+    "pa11y-webservice-client-node": "^2.0.0",
+    "pa11y-webservice": "^3.0.0",
     "underscore": "~1.8"
   },
   "devDependencies": {