maint: add yapf to dependencies

Author: mgxd

nipype/info.py

@@ -148,6 +148,7 @@ def get_nipype_gitversion():
     'pydotplus',
     'pydot>=%s' % PYDOT_MIN_VERSION,
     'packaging',
+    'yapf'
 ]
 
 if sys.version_info <= (3, 4):

requirements.txt

@@ -15,3 +15,4 @@ mock
 pydotplus
 pydot>=1.2.3
 packaging
+yapf