Actions failing—deprecated action error.

[ChristopherChudzicki]

Description/Context

Github actions appear to be failing with the following deprecation error:

 This request has been automatically failed because it uses a deprecated version of `actions/cache: 3624ceb22c1c5a301c8db4169662070a689d9ea8`. Please update your workflow to use v3/v4 of actions/cache to avoid interruptions. Learn more: https://github.blog/changelog/2024-12-05-notice-of-upcoming-releases-and-breaking-changes-for-github-actions/#actions-cache-v1-v2-and-actions-toolkit-cache-package-closing-down

Let's fix this by updating the workflow files.