Fixup CMakeLists.txt (#41)

CMake Warning (dev) at CMakeLists.txt:1 (project):
  cmake_minimum_required() should be called prior to this top-level project()
  call.  Please see the cmake-commands(7) manual for usage documentation of
  both commands.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMakeLists.txt

@@ -1,7 +1,7 @@
-project(carlsim)
-
 cmake_minimum_required(VERSION 3.21.0)
 
+project(carlsim)
+
 # specify the C++ standard aligned to YARP
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED True)