[CI] Upgraded Actions

[AlexandreSinger]

The Annotations section of the CI was full of deprecation warnings:

Node.js 16 actions were deprecated. Upgraded setup-python, checkout, and upload-artifact to their most recent version. See: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

v3 of upload-artifact was also deprecated. v4 claims to be 98% faster, however, may come with some breaking changes. Pertaining to us, artifacts cannot have the same name now and there is a limit of 500 artifacts. See: https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/

Upgrade summary:

• actions/setup-python@v4 -> actions/setup-python@v5
• actions/checkout@v3 -> actions/checkout@v4
• actions/upload-artifact@v3 -> actions/upload-artifact@v4

NOTE: Had to leave the nightly tests behind since the self-hosted machine does not support node20. Need to upgrade the machine in order to upgrade these actions.

[AlexandreSinger]

@vaughnbetz What do you think about these changes? This has removed most of the warnings except for 1, which I put a comment in the CI code with a TODO regarding upgrading the self-hosted runners:

This also made it easier to download artifacts for the nightly tests since it now separates them out into their own artifacts:

[vaughnbetz]

Sounds great -- thanks! Merging these in. Upgrading the self-hosted ones before node 16 goes away forever is definitely a good idea too. Not sure what we have to do to make that happen, and if we need Herman's help (since it is on a google cloud machine).