SDL_mixer: cmake: bump CMake policy compatibility level to 4.0

SDL Commits
1 
From 6509f9f2117513bd8d6677c4370194be932b1fe8 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sat, 12 Apr 2025 18:28:59 +0200
Subject: [PATCH] cmake: bump CMake policy compatibility level to 4.0

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5220b3c5..5f3644ab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.16...3.28)
+cmake_minimum_required(VERSION 3.16...4.0)
 
 if(NOT DEFINED CMAKE_BUILD_TYPE)
   set(cmake_build_type_undefined 1)