Fix python3 find package

[hjmjohnson]

Update to remove deprecated find_package(PythonLib) and find_package(PythonInterp) and the associated variables.

Use find_package(Python3) and its associated variables.

[hjmjohnson]

@dzenanz Thanks for the comment. I made this change, and also will be forcing ITK to 3.7 or greater soon.

[github-actions[bot]]

🎉 Published on https://examples.itk.org as production 🚀 Deployed on https://630001dd3a95cb430f50e569--itkexamples.netlify.app

[thewtex]

@hjmjohnson could this please be rebased on master?

[jhlegarreta]

@dzenanz Thanks for the comment. I made this change, and also will be forcing ITK to 3.7 or greater soon.

The CI workflow already uses 3.9, https://github.com/InsightSoftwareConsortium/ITKSphinxExamples/blob/master/.github/workflows/build-test-publish.yml#L37

and Python 3.7 is 5 months from deprecation, so if a minimum version needs to be enforced, maybe it should be 3.8. At the same time:

• We are 11 months away from 3.8 deprecation
• I have also the feeling that many have jumped to 3.10 from 3.8, so not sure if 3.9 has been a widely adopted version.

[hjmjohnson]

FYI:

ccmake -GNinja -B  ~/Dashboard/src/SphinxExamples-bld -S ~/Dashboard/src/ITK/Modules/Remote/SphinxExamples; 
cd  ~/Dashboard/src/SphinxExamples-bld && ninja

This builds successfully.

[hjmjohnson]

This is also working:

 ccmake "-DCMAKE_BUILD_TYPE:STRING=Release" "-GNinja" -B SphinxExamples-bld -S ~/Dashboard/src/ITK/Modules/Remote/SphinxExamples/Superbuild
 cd SphinxExamples-bld
 ninja

[hjmjohnson]

This works locally, but the GitHub actions are all broken for all PRS.