setup.cfg: fix license (#65)

Author: mathause

setup.cfg

@@ -2,14 +2,14 @@
 name = mplotutils
 description = utilities for matplotlib and cartopy
 author = mathause
-author_email = mathause@ethz.com
+author_email = mathias.hauser@env.ethz.com
 license = GPLv3
 url = https://github.com/mathause/mplotutils
 long_description_content_type=text/markdown
 long_description = file: README.md
 classifiers =
     Development Status :: 4 - Beta
-    License :: OSI Approved :: GNU General Public License v3 (GPLv3)
+    License :: OSI Approved :: MIT License
     Operating System :: OS Independent
     Intended Audience :: Science/Research
     Programming Language :: Python