[cmake] CPMUtil rewrite of the day number 852 (#4130)

Composite PR for several changes to CPMUtil, most notably:
- https://git.crueter.xyz/CMake/CPMUtil/pulls/19
- https://git.crueter.xyz/CMake/CPMUtil/pulls/22
- https://git.crueter.xyz/CMake/CPMUtil/pulls/24
- https://git.crueter.xyz/CMake/CPMUtil/pulls/25

These contain a lot of changes that generally simplify control flow and improve ease-of-use. Read those descriptions and patchsets for more info.

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4130
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

tools/cpm/cmake/update.cmake

@@ -0,0 +1,33 @@
+#!/usr/bin/env -S cmake -P
+
+# SPDX-FileCopyrightText: Copyright 2026 crueter
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+cmake_minimum_required(VERSION 3.31)
+
+include(${CMAKE_CURRENT_LIST_DIR}/ScriptUtils.cmake)
+
+# Update CPMUtil and its tooling/etc
+set(pwd ${CMAKE_SOURCE_DIR})
+
+set(host "https://git.crueter.xyz")
+set(repo "CMake/CPMUtil")
+set(release "releases/download/continuous")
+set(filename CPMUtil.tar.zst)
+
+mktempdir(TMP)
+
+# Download tarball
+set(url "${host}/${repo}/${release}/${filename}")
+set(file ${TMP}/${filename})
+
+cpm_download(${url} ${file})
+
+# Extract to current working directory
+file(ARCHIVE_EXTRACT
+    INPUT ${file}
+    DESTINATION ${pwd})
+
+# done :)
+echo("Updated CPMUtil")
+file(REMOVE_RECURSE ${TMP})