sty: add yapf to extras installs

Author: satra

nipype/info.py

@@ -158,6 +158,7 @@ def get_nipype_gitversion():
 EXTRA_REQUIRES = {
     'doc': ['Sphinx>=1.4', 'matplotlib', 'pydotplus', 'pydot>=1.2.3'],
     'tests': TESTS_REQUIRES,
+    'specs': ['yapf'],
     'nipy': ['nitime', 'nilearn', 'dipy', 'nipy', 'matplotlib'],
     'profiler': ['psutil>=5.0'],
     'duecredit': ['duecredit'],