启动egg-mongoose出现警告

(node:37366) [MONGODB DRIVER] Warning: Current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.

(Use `node --trace-warnings ...` to show where the warning was created)

(node:37366) DeprecationWarning: collection.ensureIndex is deprecated. Use createIndexes instead.

在启动时，如何消除这个两个警告