Update Rebel Build Action's GitHub Actions

[madmiraal]

When using Rebel Build Action the following warning is being raised:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3, actions/cache@v3, actions/upload-artifact@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

The end-of-life date for Node.js 16 was brought forward by seven months to coincide with the end of support of OpenSSL 1.1.1 on 11th September 2023.[1]. This prompted GitHub to initiate the deprecation process for GitHub Actions using Node.js 16 and transition all actions to run on Node 20 by Spring 2024.[2].

This PR upgrades the GitHub Actions that Rebel Build Action uses to the latest versions:

• actions/cache: v4
• actions/checkout: v4
• actions/upload-artifact: v4

It includes updating the Build Tests' workflow to use GitHub's checkout action to v4 too.

[1] https://nodejs.org/en/blog/announcements/nodejs16-eol/
[2] https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

[DanielaOrtner]

Thank you for keeping us all up to date on versions! :)