Add HEBO.

[AntGro]

Adding a link to the HEBO repo that contains various libraries to perform balck-box optimization and in particular automated hyperparameter tuning of ML models. The name of the repo itself refers to the method Heteroscedastic Evolutionary Bayesian optimization that won the NeurIPS 2020 Black-Box Optimisation Challenge (a competition where the testbench was a set of ML hyperparameter tuning tasks).