Cache failures shouldn't kill the jobs

[ManasJayanth]

Along with #13 , cache failures such as

Error: Unable to reserve cache with key build-darwin-arm64-6e54f555c98a94353c6fe600c1d2a2acb4b678152cb3960d58ae5ccec69c382d-20240515-1, another job may be creating this cache.

ref

.. should not stop other jobs from proceeding. Cache restores are after all optional. They should notify the user, however.