As of today, we are currently using CMake 3.21.0.
$ cmake --version
cmake version 3.21.0
We are hitting this warning because our minimum requirement is 2.6.
$ cmake ..
CMake Deprecation Warning at CMakeLists.txt:13 (cmake_minimum_required):
Compatibility with CMake < 2.8.12 will be removed from a future version of
Update the VERSION argument <min> value or use a ...<max> suffix to tell
CMake that the project does not need compatibility with older versions.