Require at least CMake 3.16

Support for < 3.5 was dropped and 3.10 deprecated in CMake 4

Author: Flamefire

CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_LEGACY_CYGWIN_WIN32 0)
-cmake_minimum_required(VERSION 2.6)
+cmake_minimum_required(VERSION 3.16..3.20)
 project(Kaguya)
 
 include(cmake/FindLua.cmake)
@@ -111,4 +111,4 @@ endif(EMSCRIPTEN)
 
 
 enable_testing()
-add_subdirectory(test)
+add_subdirectory(test)