Mnemosyne 2.11 released

[Peter Bienstman]

https://mnemosyne-proj.org/download-mnemosyne.php

- Add support for ruby/furigana, i.e '私[わたし]' will render with the

  furigana above the kanji.

- Mnemosyne can now also be installed on top of an existing Python

  installation by doing 'pip install mnemosyne-proj'. This also opens the

  door to an up-to-date install on MacOS.

- Upgrade build system to poetry and test system to Pytest (patch by Ace

  Z. Alba and kuraga).

- Fix more errors in 'Non-latin point size increase' (reported by Hugo

  Coolens).

- Improve icon finding logic (patch by traveller1).

- Fix not remembering last statistics page in some cases (patch by

  Andreas Perstinger).

- Fix rare threading issue in sync server.