doc: add note re term-size commit on top of npm

Until npm updates update-notifier to a newer version, the dependency
tree will contain a version of term-size that has an unsigned macOS
binary. This will fail .pkg notarization and will result in failed
release builds. We built and signed a term-size and contributed it back
to the project for this purpose, but the dependency chain is long enough
that it's not likely to be included in a new npm very quickly.
Until it is, we need to cherry-pick commit d2f08a1b ontop of any npm
updates to master and any other release branch that includes
notarization.

PR-URL: https://github.com/nodejs/node/pull/32403


Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>