Add logic to use different FindPackage for python if cmake is above 3.12

[syntheticgio]

find_package(PythonInterp) has been deprecated since cmake 3.5 and is throwing a warning as of 3.27 (maybe earlier). Since the minimum required version is 3.5 for this repo, added a branch to use the appropriate find_package depending on the version.

Tested with 3.27 (above the split) and 3.10.x (below the split). Both were successful for me (ubuntu:18.04 & 22.04).