Adapt for current Frescobaldi packaging and test LilyPond autoinstallation

[jeanas]

@fedelibre This is my attempt at fixing the issues in #36.

[flathubbot]

Started test build 56944

[jeanas]

Uh, I forgot tox's dependencies.

dependencies = [
  "cachetools>=5.3.1",
  "chardet>=5.1",
  "colorama>=0.4.6",
  "filelock>=3.12.2",
  'importlib-metadata>=6.7; python_version < "3.8"',
  "packaging>=23.1",
  "platformdirs>=3.8",
  "pluggy>=1.2",
  "pyproject-api>=1.5.2",
  'tomli>=2.0.1; python_version < "3.11"',
  'typing-extensions>=4.6.3; python_version < "3.8"',
  "virtualenv>=20.23.1",
]

[flathubbot]

Build 56944 failed

[flathubbot]

Started test build 56953

[flathubbot]

Build 56953 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/39575/org.frescobaldi.Frescobaldi.flatpakref

[jeanas]

Good!

I'm in a place with limited Internet access right now, so I'll let other people test the build.

[flathubbot]

Started test build 57025

[flathubbot]

Build 57025 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/39648/org.frescobaldi.Frescobaldi.flatpakref

[fedelibre]

I made a quick test and it works great!

[jeanas]

Good, thank you!

[jeanas]

What should we do with this PR now? Most of this will also be useful for the 3.4 release. Should I just close it and let you adapt it when we release 3.4?

[fedelibre]

You can either close it or set it as draft so we can modify it when 3.4 is released (probably in September?)