Increase cmake min ver to avoid warnings
When building ParaView, this warning shows up:
CMake Deprecation Warning at ThirdParty/QtTesting/vtkqttesting/CMakeLists.txt:1 (CMAKE_MINIMUM_REQUIRED):
Compatibility with CMake < 3.5 will be removed from a future version of
CMake.
Update the VERSION argument <min> value or use a ...<max> suffix to tell
CMake that the project does not need compatibility with older versions.
This MR fixes it.
Edited by Mathieu Westphal (Kitware)