Update the project url (#194)

Author: jtpio

setup.cfg

@@ -8,7 +8,7 @@ license = BSD-3-Clause
 license_files = LICENSE
 author = Jupyter Development Team
 author_email = [email protected]
-url = https://jupyter.org
+url = https://github.com/jupyter/nbclassic
 platforms = Linux, Mac OS X, Windows
 keywords = ipython, jupyter, interactive, interpreter, shell, web
 classifiers =
@@ -98,4 +98,4 @@ exclude =
     .cache,
     .github,
     docs,
-    setup.py
+    setup.py