Port the crate to use chrono instead of time

[sylvestre]

Context: uutils/coreutils#4917

[codecov]

Codecov Report

Merging #11 (6ba55a0) into main (f1a15ab) will decrease coverage by 34.07%.
The diff coverage is 64.00%.

❗ Current head 6ba55a0 differs from pull request most recent head 1d78cc5. Consider uploading reports for the commit 1d78cc5 to get more accurate results

@@             Coverage Diff             @@
##             main      #11       +/-   ##
===========================================
- Coverage   75.74%   41.68%   -34.07%     
===========================================
  Files           2        2               
  Lines         301      511      +210     
  Branches       61      103       +42     
===========================================
- Hits          228      213       -15     
- Misses         31      256      +225     
  Partials       42       42               

Flag	Coverage Δ
macos_latest	41.68% <64.00%> (-34.07%)	⬇️
ubuntu_latest	41.68% <64.00%> (-34.07%)	⬇️
windows_latest	42.68% <66.66%> (-33.07%)	⬇️

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Impacted Files	Coverage Δ
src/lib.rs	30.12% <52.63%> (-40.35%)	⬇️
tests/simple.rs	85.84% <100.00%> (+0.66%)	⬆️