fix support node 8

Author: liborm85

package.json

@@ -34,7 +34,7 @@
     "rewire": "^5.0.0",
     "sinon": "^9.2.2",
     "string-replace-webpack-plugin": "^0.1.3",
-    "terser-webpack-plugin": "4.2.3",
+    "terser-webpack-plugin": "2.3.8",
     "transform-loader": "^0.2.4",
     "webpack": "^4.44.2"
   },