Merge pull request #404 from martinRenou/update_nbconvert_travis

Update nbconvert

.travis.yml

@@ -18,7 +18,7 @@ before_install:
   - conda config --set always_yes yes --set changeps1 no
   - conda update -q conda
   - conda info -a
-  - conda create -q -n test-environment -c conda-forge python=$PYTHON_VERSION jupyter_server==0.1.0 jupyterlab_pygments==0.1.0 pytest==3.10.1 nbconvert=5.5 pytest-cov nodejs flake8 ipywidgets matplotlib xeus-cling
+  - conda create -q -n test-environment -c conda-forge python=$PYTHON_VERSION jupyter_server==0.1.0 jupyterlab_pygments==0.1.0 pytest==3.10.1 nbconvert=5.6 pytest-cov nodejs flake8 ipywidgets matplotlib xeus-cling
   - source activate test-environment
 install:
   - pip install ".[test]"

setup.py

@@ -376,7 +376,7 @@ def get_data_files():
     },
     'install_requires': [
         'jupyter_server>=0.1.0,<0.2.0',
-        'nbconvert>=5.5.0,<6',
+        'nbconvert>=5.6.0,<6',
         'jupyterlab_pygments>=0.1.0,<0.2',
         'pygments>=2.4.1,<3'  # Explicitly requiring pygments which is a second-order dependency.
                               # An older versions is generally installed already and is otherwise not updated by pip.