update to LGPL v3+ (3 or later)

Author: Georg Schramm

setup.py

@@ -15,7 +15,7 @@
     packages=setuptools.find_packages(exclude = ["data","examples","tutorial"]),
     classifiers=[
         "Programming Language :: Python :: 3",
-        "License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)",
+        "License :: OSI Approved :: GNU Lesser General Public License v3 or later (LGPLv3+)",
         "Operating System :: OS Independent",
     ],
     python_requires='>=3.6',