`findOneAndUpdate()` and `findOneAndDelete()` without the `useFindAndModify` opt code example
Example 1: DeprecationWarning: current Server Discovery and Monitoring engine is deprecated,
mongoose.connect(uri, { useNewUrlParser: true,useUnifiedTopology:true });
mongoose.createConnection(uri, { useNewUrlParser: true });
Example 2: https://mongoosejs.com/docs/deprecations.html#findandmodify
// Make Mongoose use `findOneAndUpdate()`. Note that this option is `true`
// by default, you need to set it to false.
mongoose.set('useFindAndModify', false);