Pin msgpack=0.6.2

This version setting is needed because newer versions of msgpack are incompatible with the pinned version of distributed.

See dask/distributed#3491

Author: emitra17

setup.py

@@ -23,6 +23,6 @@
       long_description=long_desc,
       author='Eshan Mitra, Ryan Suderman, Alex Ionkov',
       package=['pybnf'],
-      install_requires=['distributed==1.24.0', 'paramiko', 'numpy', 'nose', 'pyparsing', 'libroadrunner>=1.5.2',
+      install_requires=['distributed==1.24.0', 'paramiko', 'msgpack==0.6.2', 'numpy', 'nose', 'pyparsing', 'libroadrunner>=1.5.2',
                         'dask==0.20.0', 'tornado >= 4.5.1, < 5.0.0'],
       python_requires=">=3.5")