build: Raise the CMake policy maximum version to 4.4

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d08a55f..162d63a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,7 @@
 #
 # SPDX-License-Identifier: libpng-2.0
 
-cmake_minimum_required(VERSION 3.14...4.2)
+cmake_minimum_required(VERSION 3.14...4.4)
 
 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 8)