chore!: upgrade immer to v10.1

[johannes-lindgren]

Upgrade immer to version 10.1. Resolves #12

According to the migration steps, the only thing we need to do is to replace the default import:

Replace all default imports: Replace import produce from "immer" with import {produce} from "immer".

I am marking this as a breaking change, because immer v10 has breaking changes.