fix yarn setup, update event stream package

update event-stream, removing malicious flatmap-stream dependency
fix for issue #148

Author: djro

package.json

@@ -122,5 +122,8 @@
     "nock": "10.0.0",
     "sqlite3": "^4.0.0",
     "ts-jest": "23.10.1"
+  },
+  "resolutions": {
+    "**/event-stream": "^4.0.1"
   }
 }