Remove deprecated datetime.datetime.utcfromtimestamp

[07pepa]

This is not a bug but should be addressed and is in source code so i will skip usual i have latest pendulum installed

Issue

https://github.com/sdispater/pendulum/blob/3e3fec6a5b66759078c5ae39c736ca95b78adbef/src/pendulum/__init__.py#L295
_datetime.datetime.utcfromtimestamp has been deprecated since 3.12 see https://docs.python.org/3/library/datetime.html#datetime.datetime.utcfromtimestamp

its replacement is datetime.fromtimestamp and did not see any changes since python 3.6 this is supporting 3.8+ so migration should be easy https://docs.python.org/3/library/datetime.html#datetime.datetime.fromtimestamp

[edgarrmondragon]

This is clearly a duplicate of #830