CI avoid matplotlib 2.1.0
Fixes
@@ -107,7 +107,7 @@ conda update --yes --quiet conda
# Configure the conda environment and put it in the path using the
# provided versions
conda create -n $CONDA_ENV_NAME --yes --quiet python numpy scipy \
- cython nose coverage matplotlib sphinx=1.6.2 pillow
+ cython nose coverage 'matplotlib=2.0.*|>2.1.0' sphinx=1.6.2 pillow
source activate testenv
pip install sphinx-gallery numpydoc
