Caches cannot be overwritten after their creation, so the date ensures the cache is refreshed daily. This is especially true since `deploy.yml` is scheduled to run daily anyways, so there will always be a cache available for `ci.yml`.

I don't think `deploy.yml` should use any cached data, in case it ever becomes invalid. This is why `deploy.yml` only stores the cache. By deleting the crates.io cache, it may increase deploy times. If this becomes an issue, I'll make a follow-up PR and undo this change.

This reverts commit 1914571.