Update Expand With Interpolators to nbformat 4.
Update Expand With Interpolators to nbformat 4.

thewtex/SimpleITK-Notebooks,InsightSoftwareConsortium/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks,thewtex/SimpleITK-Notebooks,InsightSoftwareConsortium/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks,thewtex/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks,InsightSoftwareConsortium/SimpleITK-Notebooks