Google cloud functions Firebase Update FieldValue.increment(1) using NodeJS - TypeError: FieldValue.increment is not a function

Im using NodeJs within google cloud functions and I want to increase the value of one parameter in one document

I initiate Firestore:

const Firestore = require('@google-cloud/firestore');
const PROJECTID = 'XXXX';     
const firestore = new Firestore({
  projectId: PROJECTID,
  timestampsInSnapshots: true    
});

And my .get() and .set() functions work correctly. But when I try to update a value incrementing it, I get errors with FieldValue.increment

I've tried:

await snapshot.ref.update({ parameter: FieldValue.increment(1) });

adding:

const FieldValue = require('firebase-admin').firestore.FieldValue;

await snapshot.ref.update({ parameter: FieldValue.increment(1) });

as explained in other sites, and:

documentRef.update(
  'parameter', Firestore.FieldValue.increment(1)
)

as explained in https://cloud.google.com/nodejs/docs/reference/firestore/latest/firestore/fieldvalue

const admin = require('firebase-admin');
increment = admin.firestore.FieldValue.increment(1);
await snapshotRef.update({ parameter: increment });

But none work.

Error:

TypeError: admin.firestore.FieldValue.increment is not a function

or

TypeError: FieldValue.increment is not a function

  "dependencies": {
    "firebase-admin": "^6.5.1",
    "nodemailer": "^6.6.1"
  }