Downgrade event stream to remove flatmap-stream

Author: kddejong

client/package-lock.json

@@ -22,6 +22,7 @@
         "vscode": "^1.1.18"
     },
     "dependencies": {
-        "vscode-languageclient": "^4.1.1"
+        "vscode-languageclient": "~4.1.3",
+        "event-stream": "=3.3.4"
     }
 }