fix: fix accidentally upgraded readable-stream

Author: 3cp

package.json

@@ -52,7 +52,7 @@
     "mkdirp": "^0.5.1",
     "node-fetch": "^2.3.0",
     "node-libs-browser": "^2.1.0",
-    "readable-stream": "^3.1.0"
+    "readable-stream": "^2.3.6"
   },
   "devDependencies": {
     "@babel/cli": "^7.2.3",