cmake: switch to C++20 standard

CMake/CompilerFlags.cmake

@@ -6,7 +6,8 @@ if(NOT ${CMAKE_CXX_COMPILER_ID} MATCHES "(Clang|GNU)")
 	message(WARNING "Compiler ${CMAKE_CXX_COMPILER_ID} may not be supported.")
 endif ()
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
+add_compile_options(-Wno-ambiguous-reversed-operator) #FIXME warning in compare operators class that is supposed to be removed after the transition to C++20 three way comparison is finished
 set(CXX_STANDARD_REQUIRED ON)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)