chore(package): update ts-loader to version 2.3.1

Author: greenkeeper[bot]

package.json

@@ -45,7 +45,7 @@
     "phantomjs-prebuilt": "2.1.14",
     "semver": "5.3.0",
     "should": "11.2.1",
-    "ts-loader": "2.3.0",
+    "ts-loader": "2.3.1",
     "tslib": "1.7.1",
     "tslint": "5.5.0",
     "tslint-loader": "3.5.3",