feat(package): update offline-plugin to version 4.5.2 (#9)

BREAKING CHANGE: update offline-plugin to version 4.5.2

Author: greenkeeperio-bot

package.json

@@ -44,7 +44,7 @@
     "typescript": "^2.0.6"
   },
   "dependencies": {
-    "offline-plugin": "^3.4.2"
+    "offline-plugin": "^4.5.2"
   },
   "peerDependencies": {
     "@easy-webpack/core": "*"