Meteor 3 writable shrinkwrap.json issue is fixed

[nachocodoner]

This is a reminder that the issue mentioned in the README.md file should no longer occur.

- Mostly supports Meteor 3 (requires making programs/server/shrinkwrap.json writable due to a bug in Meteor 3)

The issue was resolved some time ago as part of Meteor 3 core updates: meteor/meteor#13219.

[1tac11]

Thx 😊