fix #3054, Bump har-validator version to 5.1.3 (#3055)

It seems that a new version of har-validator (5.1.2) may have been published, and then deleted. This PR explicitly sets the version to the latest patch, 5.1.3.

Closes #3054

package.json

@@ -34,7 +34,7 @@
     "extend": "~3.0.2",
     "forever-agent": "~0.6.1",
     "form-data": "~2.3.2",
-    "har-validator": "~5.1.0",
+    "har-validator": "~5.1.3",
     "http-signature": "~1.2.0",
     "is-typedarray": "~1.0.0",
     "isstream": "~0.1.2",