Do not use Path objects as a context manager

pathlib.Path.__enter__() is deprecated and scheduled for removal
in Python 3.13. Some warnings are generated with Python 3.11:

/usr/bin/ci-license-scan:267: DeprecationWarning: pathlib.Path.__enter__() is deprecated and scheduled for removal in Python 3.13; Path objects as a context manager is a no-op
  with Path('debian') / 'copyright-scan-patterns.yml' as scan_patterns:
/usr/bin/ci-license-scan:280: DeprecationWarning: pathlib.Path.__enter__() is deprecated and scheduled for removal in Python 3.13; Path objects as a context manager is a no-op
  with Path('debian') / 'fill.copyright.blanks.yml' as debian_copyright_overrides:
/usr/bin/ci-license-scan:296: DeprecationWarning: pathlib.Path.__enter__() is deprecated and scheduled for removal in Python 3.13; Path objects as a context manager is a no-op
  with Path('debian') / 'apertis' / 'copyright.yml' as apertis_copyright_overrides:
/usr/bin/ci-license-scan:204: DeprecationWarning: pathlib.Path.__enter__() is deprecated and scheduled for removal in Python 3.13; Path objects as a context manager is a no-op

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>