update for utcnow deprecation

[atravitz]

resolves #404

it looks like datetime.datetime.now(tz=datetime.UTC) adds timezone information that breaks some string conversion on the js side. using datetime.datetime.now(tz=None) resolves that, but I think I'd prefer to find a solution that passes datetime.UTC to be more explicit.

[codecov]

Codecov Report

❌ Patch coverage is 76.47059% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.48%. Comparing base (3ef7942) to head (7476197).
⚠️ Report is 13 commits behind head on main.

Files with missing lines	Patch %	Lines
alchemiscale/compute/api.py	33.33%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #418      +/-   ##
==========================================
- Coverage   80.55%   80.48%   -0.07%     
==========================================
  Files          27       27              
  Lines        3888     3890       +2     
==========================================
- Hits         3132     3131       -1     
- Misses        756      759       +3     

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[dotsdl]

Thanks @atravitz! We definitely want to ensure our times are in UTC to avoid local times being reported between services that are geographically separated. Can you set these changes to use datetime.datetime.now(tz=datetime.UTC) and we can then work out how to fix the breakages?

[dotsdl]

Hey @atravitz, were you able to loop back onto this one? No rush if not!

[dotsdl]

Great work @atravitz and @ianmkenney! This is a very clean solution!