Cython 3.1.0 breaks compilation

[redusys]

Cython 3.1.0 was released on the 2025-05-08, and seems to break pulls of bencoder.pyx:

  × Failed to build `bencoder-pyx==3.0.1`
  ├─▶ The build backend returned an error
  ╰─▶ Call to `setuptools.build_meta.build_wheel` failed (exit status: 1)

      [stdout]
      Compiling bencoder.pyx because it changed.
      [1/1] Cythonizing bencoder.pyx

      [stderr]
      <string>:7: SetuptoolsDeprecationWarning: The test command is disabled and references to it are deprecated.
      !!

              ********************************************************************************
              Please remove any references to `setuptools.command.test` in all supported versions of the affected package.

              This deprecation is overdue, please update your project and remove deprecated
              calls to avoid build errors in the future.
              ********************************************************************************

      !!

      Error compiling Cython file:
      ------------------------------------------------------------
      ...


      encode_func = {
          int: encode_int,
          bool: encode_int,
          long: encode_long,
          ^
      ------------------------------------------------------------

      bencoder.pyx:152:4: undeclared name not builtin: long