Fix lint error in Fibers size setting

server/authentication.js

@@ -1,10 +1,11 @@
+import Fiber from 'fibers';
+
 Meteor.startup(() => {
 
   // Node Fibers 100% CPU usage issue
   // https://github.com/wekan/wekan-mongodb/issues/2#issuecomment-381453161
   // https://github.com/meteor/meteor/issues/9796#issuecomment-381676326
   // https://github.com/sandstorm-io/sandstorm/blob/0f1fec013fe7208ed0fd97eb88b31b77e3c61f42/shell/server/00-startup.js#L99-L129
-  import Fiber from "fibers";
   Fiber.poolSize = 1e9;
 
   Accounts.validateLoginAttempt(function (options) {