Unpin cachetools in edx-repo-health due to version conflicts

[ktyagiapphelix2u]

Pinning cachetools==5.5.2 due to version conflicts that cause repo health workflow failures.
link: https://github.com/openedx/edx-repo-health/actions/runs/16510678524/job/46700605303#step:6:911
Unpin once the issue is resolved

[ktyagiapphelix2u]

PR Link : #599