Update python-chess to 0.25.1

[pyup-bot]

This PR updates python-chess from 0.24.2 to 0.25.1.

Changelog

0.25.0

--------------

New features:

* This release introduces a new **experimental API for chess engine
communication**, `chess.engine`, based on `asyncio`. It is intended to
eventually replace `chess.uci` and `chess.xboard`.

Bugfixes:

* Fixed race condition in LRU-cache of open Syzygy tables. The LRU-cache is
enabled by default (*max_fds*).
* Fix deprecation warning and unclosed file in setup.py.
Thanks Mickaël Schoentgen.

Changes:

* `chess.pgn.read_game()` now ignores BOM at the start of the stream.
* Removed deprecated items.

Links

• PyPI: https://pypi.org/project/python-chess
• Changelog: https://pyup.io/changelogs/python-chess/
• Repo: https://github.com/niklasf/python-chess

Resolves #611
Resolves #623