fix dev image build error

Author: yi.wu

Dockerfile

@@ -41,7 +41,7 @@ RUN pip install --upgrade pip && \
     pip install -U wheel pillow BeautifulSoup && \
     pip install -U docopt PyYAML sphinx && \
     pip install -U sphinx-rtd-theme==0.1.9 recommonmark && \
-    pip install -U pre-commit 'requests==2.9.2' jupyter
+    pip install pre-commit 'requests==2.9.2' 'ipykernel==4.6.0' jupyter
 
 RUN curl -sSL https://cmake.org/files/v3.4/cmake-3.4.1.tar.gz | tar -xz && \
     cd cmake-3.4.1 && ./bootstrap && make -j `nproc` && make install && \