Different license versions

[stefan6419846]

The code currently states different versions of the LGPL. Which is the correct one?

Current statements:

• LGPLv2.1:

  func_timeout/setup.py

  Line 4 in 50baa8d

  This software is licensed under the terms of the Lesser GNU General Public License Version 2.1 (LGPLv2.1)

• LGPLv2:

  func_timeout/setup.py

  Line 46 in 50baa8d

  'License :: OSI Approved :: GNU Lesser General Public License v2 (LGPLv2)',

• LGPLv3 for the files in func_timeout, tests and the LICENSE file itself.