ci: Fix "Unsupported engine" error

[seanpoulter]

Background

The build is failing because npm@latest does not support Node.js v16.
From https://github.com/webdriverio-community/wdio-rerun-service/actions/runs/8117449278/job/22189648193:

Run npm i -g npm@latest
  npm i -g npm@latest
  shell: /usr/bin/bash -e {0}
npm ERR! code EBADENGINE
npm ERR! engine Unsupported engine
npm ERR! engine Not compatible with your version of node/npm: [email protected]
npm ERR! notsup Not compatible with your version of node/npm: [email protected]
npm ERR! notsup Required: {"node":"^18.17.0 || >=20.5.0"}
npm ERR! notsup Actual:   {"npm":"8.19.4","node":"v16.20.2"}

Proposed Changes

• ci: Use a supported version of npm, not npm@latest
• ci: Bump actions/checkout from v3 to v4
• ci: Bump actions/setup-node from v3 to v4

[christian-bromann]

👍