Fixed datetime deprecation warning

[exploide]

datetime.utcfromtimestamp() is deprecated, timezone-aware datetime objects should be used instead.

This fixes a deprecation warning that appears in Python 3.12+.

[cddmp]

Hi @exploide,
sorry for my late reply, there were lots of things going on during the last days!
Thank you for your continous support of this tool, I really appreciate that.
The PR looks good, just one question, since I haven't tested it so far:
Have you tested with which Python versions it might break?

[exploide]

No problem, thanks for replying. :)

I haven't tested older versions but this is nothing I expect to break. datetime.fromtimestamp exists back to Python 2.7 and I found timezone.utc being mentioned in the docs of 3.5.

[exploide]

Just tested the relevant portions of the code in a container. Even works down to Python 3.2:

Python 3.2.6 (default, Jan 18 2016, 19:21:14) 
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime, timezone
>>> tmp = 123456789
>>> dt = datetime.fromtimestamp(tmp, tz=timezone.utc)
>>> minutes = dt.minute
>>> hours = dt.hour
>>> time_diff = dt - datetime.fromtimestamp(0, tz=timezone.utc)
>>> print(time_diff.days)
1428

[cddmp]

Looks good!