update time crate (fixes coverage)

[nothingmuch]

cargo llvm-cov breaks with the older time crate due to use of hence removed no_coverage feature

[nothingmuch]

as of #55 & #60, running cargo llvm-cov is still broken as now the pinned version of time is locked at 0.3.20.

this PR needs to be updated to fix #43, where Cargo-recent can allow llvm-cov and Cargo-minimal maintains MSRV

[benalleng]

I think we can close this as time is now at version v0.3.41 following our update to the msrv to 1.85.0. Additionally I tested cargo llvm-cov on our latest main commit and can confirm that it works, though our coverage is abysmal