Bump action versions to avoid deprecation

[orhoj]

Purpose

Version 2 of our action dependencies used node 12 which GitHub complains about. This bumps the versions to v3 that should not have this issue.

Changes

• actions/upload-artifact@v2 --> actions/upload-artifact@v3
• actions/checkout@v2 --> actions/checkout@v3

Checklist

• [x] My code follows the style of this project.
• [x] The code compiles without warnings.
• [x] I have performed a self-review of the changes.
• [x] I have documented my code, in particular the intent of the hard-to-understand areas.
• [x] (If necessary) I have updated the CHANGELOG.