chore: Replace deprecated utcnow()

[winniehell]

What does this PR do?

replace datetime.datetime.utcnow() with datetime.datetime.now(datetime.timezone.utc) to resolve deprecation warnings

see warning in Python documentation: https://docs.python.org/3.8/library/datetime.html#datetime.datetime.utcnow

[winniehell]

@willingc do you have time to take a look at this tiny change? it would safe us a few deprecation warnings in our logs 🙂

[winniehell]

@MSeal do you have time to take a look at this?

[rgbkrk]

Thank you. Not sure what's up with CI not reporting back.

[winniehell]

I tried to trigger CI with another push but it doesn't seem to help 🤷

[winniehell]

https://github.com/nteract/papermill/actions/runs/19180999485 displays This workflow is awaiting approval from a maintainer in https://github.com/nteract/papermill/pull/823 for me:

[rgbkrk]

Odd that can't trigger it from here. When I get back to my laptop I'll change the repo settings to modern GitHub actions so we can kick this off and clean up the backlog of PRs.

[winniehell]

according to https://docs.github.com/en/actions/how-tos/manage-workflow-runs/approve-runs-from-forks, there should be an approve button here on the conversations tab though I'm not sure where or how it looks like