Switch to `pytest-freezer`

[mtelka]

Description

pytest-freezegun was replaced by pytest-freezer so please change yamlfix to use pytest-freezer.
More details: ktosiek/pytest-freezegun#44

Steps to reproduce

NA

Current behavior

The abandoned pytest-freezegun is used.

Desired behavior

The pytest-freezer replacement is used instead.

Screenshots
NA

Environment

NA

[mtelka]

OTOH, is pytest-freezegun used by yamlfix? I'm unable to find any reference to it in yamlfix sources.