fix(package): update readable-stream to version 3.4.0

Closes #10

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "antlr4": "^4.5.3",
     "js_antlr": "1.0.0",
     "lodash.escaperegexp": "^4.1.2",
-    "readable-stream": "^2.1.5"
+    "readable-stream": "^3.4.0"
   },
   "devDependencies": {
     "chai": "^4.0.1",