Upgrade to upload/download v4 (v3 is deprecated)

[sbernard31]

GitHub has issued a deprecation notice for some commonly used actions.

• actions/upload-artifact
• actions/download-artifact

The following versions are deprecated and will stop working in the not so near future:

• v1 and v2: from 30/06/2024
• v3: from 30/11/2024

It is highly encouraged to update to v4 of these actions asap to avoid any disruption.

See more details at:

• https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/
• https://github.blog/changelog/2024-02-13-deprecation-notice-v1-and-v2-of-the-artifact-actions/