GitHub actions

[jnyrup]

I got an email from GitHub because I had workflows using v3 of actions/download-artifact or actions/upload-artifact, so updating repos I have forks of.

While here I did a bit more cleanup to remove warnings from CI.

IMPORTANT

• If the PR touches the public API, the changes have been approved in a separate issue with the "api-approved" label.
• The code complies with the Coding Guidelines for C#.
• The changes are covered by unit tests which follow the Arrange-Act-Assert syntax and the naming conventions such as is used in these tests.
• If the PR changes the public API the changes needs to be included by running AcceptApiChanges.ps1 or AcceptApiChanges.sh.