Add CMake maximum version

Installation has been tested with CMake `3.27`. Adding the maximum
version rids us of a warning message concerning policy CMP0144.

CMakeLists.txt

-cmake_minimum_required(VERSION 3.20)
+cmake_minimum_required(VERSION 3.20...3.27)
 project(Detection_eddies LANGUAGES Fortran)
 set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS Debug Release Profile
   RelWithDebInfo)