Compatibility with mongo driver V4

[rmanibus]

Steps to reproduce

This extension is not compatible with the mongodb driver v4.

after create I have the following error:

error: Unhandled Rejection at: Promise  {"hook":{"type":"before","method":"create","path":"api/users","params":{},"data":{"visible":true,"name":"ADMIN","password":"$2a$10$97XORKjmdC55IFVbXB1myucvdC8JCa9Wx2udSD.K93s8IZwO9A80S","permissions":["ADMIN"]}}}
TypeError: Cannot read property 'length' of undefined
    at C:\Users\loich\workspace\project\node_modules\feathers-mongodb\lib\index.js:214:46
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {

It is failing on:

    const promise = Array.isArray(data)
      ? this.Model.insertMany(data.map(setId), options)
      : this.Model.insertOne(setId(data), options);

    return promise.then(result => result.ops.length > 1 ? result.ops : result.ops[0])
      .then(select(params, this.id))
      .catch(errorHandler);

It seems that the return format for insertOne changed : https://github.com/mongodb/node-mongodb-native/blob/4.1/docs/CHANGES_4.0.0.md