Currently, cmake is emitting the following warning:
```
CMake Deprecation Warning at cmake/ccache.cmake:23 (cmake_minimum_required):
Compatibility with CMake < 3.5 will be removed from a future version of
CMake.
```
Update the CMake min version to 3.5 to unclutter the build logs and ensure users don't get broken by the deprecation.
Mateusz Pusz
Nick Thompson
Markus Hofbauer