notify users when they're on an old version

[zeke]

Is your feature request related to a problem? Please describe.

If people don't use the latest, they don't get the greatest.

Describe the solution you'd like

When a user runs this CLI on an old version, it should do a version check and let them know how to upgrade.

Could be npm i -g create-replicate or npx create-replicate@latest.

Describe alternatives you've considered

An alternative would be to display npx create-replicate@latest everywhere, so people are more likely to always be running latest.

But that's not ideal because it looks ugly, and people who aren't reading the docs will still likely run it wihout the @latest