Change dashes with underscores

Change include-package-data to include_package_data, because include-package-data will stop working in the future.

Author: AttackingOrDefending

setup.cfg

@@ -19,7 +19,7 @@ classifiers =
     Topic :: Software Development :: Libraries :: Python Modules
 
 [options]
-include-package-data = true
+include_package_data = true
 packages =
     tictactoe
 python_requires = >=3.6