Install parse-server 3.9.0 insted of 2.2 (#6069)

The script currently writes a package.json with a dependency on parse-server version 2.2. This should probably always be automatically updated to the latest version using some CI magic.

bootstrap.sh

@@ -163,7 +163,7 @@ cat > ./package.json << EOF
     "start": "parse-server config.json"
   },
   "dependencies": {
-    "parse-server": "^2.0.0"
+    "parse-server": "^3.9.0"
   }
 }
 EOF