use latest version of javascript-obfuscator

fix for javascript-obfuscator/javascript-obfuscator#452

Author: Camlan1

package-lock.json

@@ -15,7 +15,7 @@
     "main": "./dist/index.js",
     "types": "./dist/index.d.ts",
     "dependencies": {
-        "javascript-obfuscator": "^0.18.6",
+        "javascript-obfuscator": "^0.18.8",
         "multi-stage-sourcemap": "^0.2.1",
         "multimatch": "^2.1.0",
         "webpack-sources": "^1.3.0"