ENH: added pip install simpleitk for testing

Author: dave3d

.github/workflows/notebook-test.yml

@@ -31,6 +31,7 @@ jobs:
           python3 -m pip install pyimagej urllib3
           python3 -c "import imagej; ij = imagej.init('2.5.0'); print(ij.getVersion())"
           python3 -m pip install "itk>=5.3.0"
+          python3 -m pip install "simpleitk>=2.5.3"
 
       - name: Test notebooks
         run: |