How to upgrade to v12 in monorepo?

I have a monorepo with two apps and one shared lib:

node_modules/
web/
    - lib/
    - apps/
        - app1/
        - app2/

Both apps and the lib have own rescript.json. Both apps have web/lib as a dependency.

How to upgrade this setup to v12?

P.S. I use npm (with workspaces) as a package manager.