Upgrade actions/cache to 4.2.0

[barchetta]

Pipeline runs are reporting:

"Your workflow is using a version of actions/cache that is scheduled for deprecation, actions/[email protected]. Please update your workflow to use either v3 or 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"

Our workflows are using 4.0.2 -- so the message is misleading. Better information here:

actions/cache#1510

Bottom line:

1. Upgrade to 4.2.0
2. If we don't upgrade things will break on March 1st, 2025