python3-packaging: upgrade 25.0 -> 26.0

python3-packaging: upgrade 25.0 -> 26.0

Skip the testcase test_pylock.py as this depends on tomli_w, which isn't
currently part of core.

Upstream changelog:

Features:

* PEP 751: support pylock
* PEP 794: import name metadata
* Support for writing metadata to a file
* Support __replace__ on Version
* Support positional pattern matching for Version and SpecifierSet

Behavior adaptations:

* PEP 440 handling of prereleases for Specifier.contains,
  SpecifierSet.contains, and SpecifierSet.filter
* Handle PEP 440 edge case in SpecifierSet.filter
* Adjust arbitrary equality intersection preservation in SpecifierSet
* Return False instead of raising for .contains with invalid version
* Support arbitrary equality on arbitrary strings for Specifier and
  SpecifierSet's filter and contains method.
* Only try to parse as Version on certain marker keys, return False on
  unequal ordered comparisons

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>