CI upgrade travis to run on new numpy release (scikit-learn#9096)

Author: amueller

.travis.yml

@@ -38,7 +38,7 @@ matrix:
     # This environment tests the newest supported Anaconda release (4.4.0)
     # It also runs tests requiring Pandas.
     - env: DISTRIB="conda" PYTHON_VERSION="3.6.1" INSTALL_MKL="true"
-           NUMPY_VERSION="1.12.1" SCIPY_VERSION="0.19.0" PANDAS_VERSION="0.20.1"
+           NUMPY_VERSION="1.13" SCIPY_VERSION="0.19.0" PANDAS_VERSION="0.20.2"
            CYTHON_VERSION="0.25.2" COVERAGE=true
     # This environment use pytest to run the tests. It uses the newest
     # supported Anaconda release (4.4.0). It also runs tests requiring Pandas.
@@ -49,7 +49,7 @@ matrix:
     # flake8 linting on diff wrt common ancestor with upstream/master
     - env: RUN_FLAKE8="true" SKIP_TESTS="true"
            DISTRIB="conda" PYTHON_VERSION="3.5" INSTALL_MKL="true"
-           NUMPY_VERSION="1.12.1" SCIPY_VERSION="0.19.0" CYTHON_VERSION="0.23.5"
+           NUMPY_VERSION="1.13" SCIPY_VERSION="0.19.0" CYTHON_VERSION="0.23.5"
     # This environment tests scikit-learn against numpy and scipy master
     # installed from their CI wheels in a virtualenv with the Python
     # interpreter provided by travis.