python-chess v0.27.0

This is the second **release candidate for python-chess 1.0**. If you see the
need for breaking changes, please speak up now!

Bugfixes:

* `EngineProtocol.analyse(*, multipv)` was not passing this argument to the
  engine and therefore only returned the first principal variation.
  Thanks @svangordon.
* `chess.svg.board(*, squares)`: The X symbol on selected squares is now more
  visible when it overlaps pieces.

Changes:

* **FEN/EPD parsing is now more relaxed**: Incomplete FENs and EPDs are
  completed with reasonable defaults (`w - - 0 1`). The EPD parser accepts
  fields with moves in UCI notation (for example the technically invalid
  `bm g1f3` instead of `bm Nf3`).
* The PGN parser now skips games with invalid FEN headers and variations after
  an illegal move (after handling the error as usual).

New features:

* Added `Board.is_repetition(count=3)`.
* Document that `chess.engine.EngineProtocol` is compatible with
  AsyncSSH 1.16.0.