chore(package): update less-loader to version 6.1.0

Closes #354

Author: greenkeeper[bot]

package.json

@@ -69,7 +69,7 @@
     "jest": "^20.0.0",
     "json-loader": "^0.5.4",
     "less": "^3.0.0",
-    "less-loader": "^4.0.3",
+    "less-loader": "^6.1.0",
     "mkdirp": "^0.5.1",
     "ncp": "^2.0.0",
     "offline-plugin": "^5.0.0",