Update setup.cfg

Updated surfa ref to point to master branch

Author: jnolan14

setup.cfg

@@ -19,7 +19,7 @@ include_package_data = True
 python_requires >= 3.6
 packages = find:
 install_requires =
-    surfa@git+https://github.com/freesurfer/surfa.git@78957160b63a01f4cbfce13b45d63d40d28f87f9
+    surfa@git+https://github.com/freesurfer/surfa.git@master
     scikit-learn
     numpy
     numba