pypi package is broken due to submodule "update_notifications"

[lukasrothenberger]

Issue:
The update_notifications submodule is not correctly included into the Pypi package.

Output:

pip install discopop
Collecting discopop
Downloading discopop-5.0.2.tar.gz (382 kB)
Installing build dependencies ... done
Getting requirements to build wheel ... error
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> [20 lines of output]
/tmp/pip-build-env-g_uy4ij7/overlay/lib/python3.14/site-packages/setuptools/dist.py:765: SetuptoolsDeprecationWarning: License classifiers are deprecated.
!!

          ********************************************************************************
          Please consider removing the following classifiers in favor of a SPDX license expression:
  
          License :: OSI Approved :: BSD License
  
          See https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license for details.
          ********************************************************************************
  
  !!
    self._finalize_license_expression()
  running egg_info
  writing discopop.egg-info/PKG-INFO
  writing dependency_links to discopop.egg-info/dependency_links.txt
  writing entry points to discopop.egg-info/entry_points.txt
  writing requirements to discopop.egg-info/requires.txt
  writing top-level names to discopop.egg-info/top_level.txt
  error: package directory 'tools/submodules/update_notifications' does not exist
  [end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.

[notice] A new release of pip is available: 25.3 -> 26.0.1
[notice] To update, run: pip install --upgrade pip
ERROR: Failed to build 'discopop' when getting requirements to build wheel