python3-babel: upgrade 2.15.0 -> 2.16.0

Changelog:
=========
- CLDR: Upgrade to CLDR 45
- Lists: Support list format fallbacks
- Messages: Initial support for reading mapping configuration as TOML
- CLDR: Do not allow substituting alternates or drafts in derived locales
- Core: Allow falling back to modifier-less locale data
- Core: Allow use of importlib.metadata for finding entrypoints
- Dates: Avoid crashing on importing localtime when TZ is malformed
- Messages: Allow parsing .po files that have an extant but empty Language
  header
- Messages: Fix --ignore-dirs being incorrectly read
- Messages: Make pgettext search plurals when translation is not found
- Replace deprecated ast.Str with ast.Constant
- Test on Python 3.13 beta releases
- Normalize package name to lower-case in setup.py
- Add a mention to the docs that format_skeleton(..., fuzzy=True) may
  raise
- Two hyperlinks (to CLDR) and some typos

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>