1.2.0

• Add EGO optimization with GEKPLS model (#340, #346, thanks @Laurentww)
• Breaking change: Remove scikit-learn < 0.22 support for KPLS surrogates family
• Remove Python 3.6 from CI tests as it has reached its end-of-life date (#342).
• Fix MOE when test data are specified (#347)
• Fix MFK to make it work even with one fidelity (#339, #341)
• Fix Kriging based surrogates to allow constant function modeling (#338)
• Fix KPLS automatic determination of components number and update notebook (#335)