upgrade engines for cli to 18.18.0, resolves error for missing `addAbortListener`

[josefaidt]

Environment information

n/a

Describe the bug

if you run ampx sandbox on node 18.16 or 18.17 you'll experience an error that node:events doesn't have addAbortListener (required from execa). this function was added in 18.18 https://nodejs.org/docs/latest-v18.x/api/events.html#eventsaddabortlistenersignal-resource

https://github.com/aws-amplify/amplify-backend/blob/main/packages/cli/package.json#L25

Reproduction steps

see above

[ykethan]

Marking as bug for further investigation.