Update actions/download-artifact and actions/upload-artifact to v4

[bact]

• v1, v2, v3 are deprecated
  • They use deprecated version of Node, which at risk of breaking soon
  • See https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/
• Do not upgrade until these bugs get fixed: [bug] actions/upload-artifact@v4 often fails, but can succeed after trying again actions/upload-artifact#642 [bug] cannot upload multiple artifacts under the same path actions/upload-artifact#626