fix(turborepo): Run update notifier on turbo that is actually executed (#3190)
To avoid running the update notifier twice, we delay running it until
the shim decides between executing local turbo or current turbo. At that
point, we check either the local turbo version or the current turbo
version and run the update notifier.
Co-authored-by: Thomas Knickman <tom.knickman@vercel.com>