fixed required scikit-learn version

for python35 environment.

Author: florian

.travis.yml

@@ -19,7 +19,7 @@ env:
       SCIKIT_VERSION="0.20.2" SCIPY_VERSION="0.17.0" STATSMODELS_VERSION="0.6.1"
     - DISTRIB="conda" PYTHON_VERSION="3.5" COVERAGE="true" CYTHON_VERSION="0.23.4"
       NUMPY_VERSION="1.11.1" PANDAS_VERSION="0.21.1" PATSY_VERSION="0.4.1"
-      SCIKIT_VERSION="0.17.1" SCIPY_VERSION="0.17.0" STATSMODELS_VERSION="0.6.1"
+      SCIKIT_VERSION="0.20.2" SCIPY_VERSION="0.17.0" STATSMODELS_VERSION="0.6.1"
 
 install: source ci_scripts/install.sh
 script: bash ci_scripts/test.sh