Update node-sass to v6.0.0

Author: toddmotto

package.json

@@ -38,7 +38,7 @@
     "karma-spec-reporter": "0.0.31",
     "karma-webpack": "2.0.4",
     "ngrx-store-freeze": "^0.2.0",
-    "node-sass": "4.5.3",
+    "node-sass": "6.0.0",
     "progress-bar-webpack-plugin": "1.9.3",
     "raw-loader": "0.5.1",
     "rimraf": "2.6.2",