Update README.md

Author: krzjoa

README.md

@@ -289,6 +289,7 @@ Curated list of data science software in Python
 * [Solid](https://github.com/100/Solid) - A comprehensive gradient-free optimization framework written in Python
 * [PySwarms](https://github.com/ljvmiranda921/pyswarms) - A research toolkit for particle swarm optimization in Python
 * [Platypus](https://github.com/Project-Platypus/Platypus) - A Free and Open Source Python Library for Multiobjective Optimization
+* [GPflowOpt](https://github.com/GPflow/GPflowOpt) - Bayesian Optimization using GPflow
 
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 ## Natural Language Processing