replace chrono feature clock with now

[tottoto]

Seems to be able to use a subset of clock feature, now which is introduced at 0.4.32.

https://github.com/chronotope/chrono/releases/tag/v0.4.32

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.1%. Comparing base (0952c2a) to head (d6d022b).

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1448   +/-   ##
=====================================
  Coverage   72.1%   72.1%           
=====================================
  Files         78      78           
  Lines       6594    6594           
=====================================
  Hits        4749    4749           
  Misses      1845    1845           

[mateiidavid]

LGTM, had a look at the diff (chronotope/chrono#1343), removes the overhead of adding timezone support.

[clux]

looks sensible, now seems to bring in only alloc and alloc seems to gate what we use (timestamp formatting generally)