CI maintenance because of deprecations on Oct 15 and Nov 30 2024

[anttiharju]

What

I made small careful commits and tried to explain each in their message. Reviewing this PR commit-by-commit might be the easiest way to understand it.

Why

https://github.blog/changelog/label/actions+deprecation/ is a good resource for staying up-to-date on action deprecations. There are a few that would affect this repo, so I went ahead and updated the build workflow.

1. End of life for Actions Node16

   From the 15th of October, we will no longer include Node16 in the Actions runner and customers will no longer be able to use Node16 Actions or operating systems that do not support Node20.

2. Deprecation notice: v3 of the artifact actions

   Starting November 30, 2024, GitHub Actions customers will no longer be able to use v3 of actions/upload-artifact or actions/download-artifact. Customers should update workflows to begin using v4 of the artifact actions as soon as possible.

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I like this app quite a bit, hopefully this PR is helpful. Thanks for all the work so far.