Update setup.cfg

Author: phinate

setup.cfg

@@ -39,7 +39,7 @@ install_requires =
     celluloid
     matplotlib
     relaxed>=0.2.0
-    sklearn
+    scikit-learn
     typing-extensions>=3.7;python_version<'3.8'
 python_requires = >=3.6
 include_package_data = True