ENH: Specify minimum allowed python version

When searching for python installation, ensure that a supported
version is found.

CMake/ITKSetPython3Vars.cmake

@@ -8,18 +8,20 @@
 # implementation gives preference to active virtualenvs.
 
 cmake_policy(SET CMP0094 NEW) # makes FindPython3 prefer activated virtualenv Python to latest version
+set(PYTHON_REQUIRED_VERSION 3.7)
+set(Python_ADDITIONAL_VERSIONS 3.12 3.11 3.10 3.9 3.8 3.7)
 if(PYTHON_DEVELOPMENT_REQUIRED)
   if(DEFINED Python3_EXECUTABLE) # if already specified
     set(_specified_Python3_EXECUTABLE ${Python3_EXECUTABLE})
   endif()
   # set(Python3_FIND_REGISTRY LAST) # default is FIRST. Do we need/want this?
-  find_package(Python3 COMPONENTS Interpreter Development)
+  find_package(Python3 ${PYTHON_REQUIRED_VERSION} COMPONENTS Interpreter Development)
   if(DEFINED _specified_Python3_EXECUTABLE)
     set(Python3_EXECUTABLE ${_specified_Python3_EXECUTABLE} CACHE INTERNAL
       "Path to the Python interpreter" FORCE)
   endif()
 else() # if not PYTHON_DEVELOPMENT_REQUIRED, just find some version of Python (don't need to be as specific)
-  find_package(Python3 COMPONENTS Interpreter)
+  find_package(Python3 ${PYTHON_REQUIRED_VERSION} COMPONENTS Interpreter)
 endif()
 if(ITK_WRAP_PYTHON)
   set(ITK_WRAP_PYTHON_VERSION "${Python3_VERSION}")