PyPI publication broken by switch to uv

[marco-c]

Traceback (most recent call last):
  File "/usr/local/bin/taskboot", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.10/site-packages/taskboot/cli.py", line 354, in main
    args.func(target, args)
  File "/usr/local/lib/python3.10/site-packages/taskboot/pypi.py", line 29, in publish_pypi
    setup = target.check_path("setup.py")
  File "/usr/local/lib/python3.10/site-packages/taskboot/target.py", line 68, in check_path
    assert os.path.exists(full_path), "Missing file in target {}".format(path)
AssertionError: Missing file in target setup.py

[marco-c]

To fix this, we need to add support in taskboot (https://github.com/mozilla/task-boot/blob/master/taskboot/pypi.py), or stop using taskboot.