CMake minimum version warning

[petrmanek]

When configuring QuickQanava with cmake 3.31.4, the following warning is printed:

CMake Deprecation Warning at lib/quickqanava/CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.10 will be removed from a future version of
  CMake.
  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.

The fix should be easy -- raise the argument of this directive to a higher version.