minimum required multipledispatch version is 0.6
As shown by gpflow does not work with older versions of multipledispatch - this change reflects this in the setup.py version requirements.
@@ -13,7 +13,7 @@ from setuptools import find_packages, setup
on_rtd = os.environ.get("READTHEDOCS", None) == "True" # copied from the docs
# Dependencies of GPflow
-requirements = ["numpy>=1.10.0", "scipy>=0.18.0", "multipledispatch>=0.4.9", "tabulate"]
+requirements = ["numpy>=1.10.0", "scipy>=0.18.0", "multipledispatch>=0.6", "tabulate"]
if sys.version_info < (3, 7):
# became part of stdlib in python 3.7
