Please update requirements to use PyYAML v6

[YarikTH]

Newest setup tools doesn't like using of deprecated metadata of PyYAML v5

  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [62 lines of output]
      /tmp/pip-build-env-m9vryc7y/overlay/lib/python3.10/site-packages/setuptools/config/setupcfg.py:293: _DeprecatedConfig: Deprecated config in `setup.cfg`
      !!
      
              ********************************************************************************
              The license_file parameter is deprecated, use license_files instead.
      
              By 2023-Oct-30, you need to update your project and remove deprecated calls
              or your builds will no longer be supported.
      
              See https://setuptools.pypa.io/en/latest/userguide/declarative_config.html for details.
              ********************************************************************************
      
      !!
        parsed = self.parsers.get(option_name, lambda x: x)(value)
      running egg_info
      writing lib3/PyYAML.egg-info/PKG-INFO
      writing dependency_links to lib3/PyYAML.egg-info/dependency_links.txt
      writing top-level names to lib3/PyYAML.egg-info/top_level.txt

According to the issue yaml/pyyaml#536 it seems that PyYAML v5 won't be fixed, and new v6 should be used instead.

[BlankSpruce]

Done. I've released 0.9.2 to cover that change.