ITK nightly version update

This commit updates:
  (1) SHA used in CMakeLists.txt to checkout ITK sources
          (InsightSoftwareConsortium/ITK@907b70aa5f)
  (2) VERSION variable set in itkVersion.py

It was automatically generated by the script update_python_version.sh [1]

[1] https://github.com/InsightSoftwareConsortium/ITKPythonPackage/blob/b5675c8/scripts/update_python_version.py

Author: kwrobot

CMakeLists.txt

@@ -74,7 +74,7 @@ if(ITKPythonPackage_SUPERBUILD)
 
   set(ITK_REPOSITORY "https://github.com/InsightSoftwareConsortium/ITK.git")
   # ITK nightly-master 2018-11-10
-  set(ITK_GIT_TAG "481d3dd2aa")
+  set(ITK_GIT_TAG "907b70aa5f")
 
   #-----------------------------------------------------------------------------
   # A separate project is used to download ITK, so that it can reused

itkVersion.py

@@ -1,4 +1,4 @@
-VERSION = '5.0b01.dev20181110+361.g481d3dd2aa'
+VERSION = '5.0b01.dev20181110+365.g907b70aa5f'
 
 def get_versions():
     """Returns versions for the ITK Python package.