chore(package): update offline-plugin to version 5.0.7

Closes #217

Author: greenkeeper[bot]

package.json

@@ -124,7 +124,7 @@
     "ngc-webpack": "^3.2.0",
     "npm-run-all": "^4.1.1",
     "npm-scripts-help": "^0.7.0",
-    "offline-plugin": "^4.8.3",
+    "offline-plugin": "^5.0.7",
     "optimize-js-plugin": "0.0.4",
     "parse5": "^3.0.1",
     "postcss": "^6.0.11",