Update actions/upload-artifact in GitHub Actions workflows to v4

[striezel]

Updates the actions/upload-artifact action used in the GitHub Actions workflow to its newest major version.

Changes in actions/upload-artifact:

v3.1.2

• Update all @actions/* NPM packages to their latest versions
• Update all dev dependencies to their most recent versions

v3.1.1

• Update actions/core package to latest version to remove set-output deprecation warning

v3.1.0

• Bump @actions/artifact to v1.1.0
  • Adds checksum headers on artifact upload

v3.0.0

• Update default runtime to node16
• Update package-lock.json file version to 2

Still using v2 of actions/upload-artifact will generate some warning like in this run: https://github.com/splitgraph/sgr/actions/runs/4606051660

Node.js 12 actions are deprecated. Please update the following actions to use Node.js 16: actions/upload-artifact@v2. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.

The PR will get rid of those warnings for actions/upload-artifact, because v3 uses Node.js 16.

[striezel]

Rebased against the current master branch and updated from v3 to v4, because the deprecation of v3 has been announced: https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/