build: update github actions checkout version

[Vickysomtee]

Describe your changes

The PR upgrades the actions checkout from version 2 to version 3.

Issue ticket number and link

N/A

Motivation and Context

The version 2 of Github actions checkout uses node 12 which is no longer a supported version of NodeJs and is also deprecated for Github Action.

Screenshots (if appropriate):

N/A

[tohuw]

This was approved back in 2023 but went stale — the conflict is just audio_backup.yml and backup.yml, which no longer exist on master. Rather than let an approved change die, I've re-applied it to the five current workflows in #837 (with @Vickysomtee as commit co-author), targeting today's stable v4 of both actions/checkout and actions/setup-node. This PR can likely be closed in its favor.

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This comment was created by Claude Fable 5 on behalf of @tohuw.