change numpy version to 1.15.2 in python install_requires

install_requires setting is used for python egg or wheel files to indicate what packages are required during the installation.
Default numpy version on ubuntu 18 is 1.15.2. I think it is safe to change numpy version in mxnet install_requires from 1.15.0 to 1.15.2.

python/setup.py

@@ -30,7 +30,7 @@
 else:
     from setuptools import setup
     from setuptools.extension import Extension
-    kwargs = {'install_requires': ['numpy<=1.15.0,>=1.8.2', 'requests<2.19.0,>=2.18.4', 'graphviz<0.9.0,>=0.8.1'], 'zip_safe': False}
+    kwargs = {'install_requires': ['numpy<=1.15.2,>=1.8.2', 'requests<2.19.0,>=2.18.4', 'graphviz<0.9.0,>=0.8.1'], 'zip_safe': False}
 
 with_cython = False
 if '--with-cython' in sys.argv: