Keras version bump

requirements.txt

 six
 numpy>=1.11
 pandas>=0.20.3
-Keras>=2.2.5
+Keras>=2.3.0
 tensorflow>=1.15.0,<2.0.0
 appdirs
 scikit-learn

setup.py

@@ -51,7 +51,7 @@ if __name__ == '__main__':
         'six',
         'numpy>=1.11',
         'pandas>=0.20.3',
-        'Keras>=2.2.5',
+        'Keras>=2.3.0',
         'appdirs',
         'tensorflow>=1.15.0,<2.0.0',
         'scikit-learn',