fix(package): update path-to-regexp to version 4.0.0

Closes #85

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
   "dependencies": {
     "history": "^4.6.3",
     "path": "^0.12.7",
-    "path-to-regexp": "^2.4.0",
+    "path-to-regexp": "^4.0.0",
     "prop-types": "^15.5.10",
     "query-string": "^4.3.4",
     "url": "^0.11.0"