chore(package): update sass-loader to version 7.0.0

Author: greenkeeper[bot]

package.json

@@ -101,7 +101,7 @@
     "rollup-plugin-uglify": "3.0.0",
     "run-sequence": "2.2.1",
     "rxjs": "5.5.2",
-    "sass-loader": "6.0.7",
+    "sass-loader": "7.0.0",
     "source-map-loader": "0.2.3",
     "to-string-loader": "1.1.5",
     "travis-status": "2.0.0",