Avoid `datetime.utcfromtimestamp` Python 3.12 deprecation warning

[scop]

Proposed change

https://docs.python.org/3.12/library/datetime.html#datetime.datetime.utcfromtimestamp

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [ ] New service (thank you!)
• [ ] New feature (which adds functionality to an existing service)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [x] Code quality improvements to existing code or addition of tests
• [ ] Documentation or code sample

Example of code:

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:

Checklist

• [ ] The code change is tested and works locally.
• [ ] Local tests pass. Your PR cannot be merged unless tests pass
• [ ] There is no commented out code in this PR.
• [ ] Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• [ ] Documentation added/updated to README