rename deprecated variable (#120)

Author: jdkent

setup.cfg

@@ -6,7 +6,7 @@ author_email = [email protected]
 maintainer = Taylor Salo
 maintainer_email = [email protected]
 description = PyMARE: Python Meta-Analysis & Regression Engine
-description-file = README.md
+description_file = README.md
 long_description =
     PyMARE: Python Meta-Analysis & Regression Engine
     ================================================