libobs: Update CMake minimum to 3.22

Since Ubuntu 22.04 is now our minimum supported Ubuntu version, and it
has CMake 3.22, let's make CMake 3.22 the minimum CMake version.

libobs-opengl/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.16...3.25)
+cmake_minimum_required(VERSION 3.22...3.25)
 
 legacy_check()
 

libobs/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.16...3.25)
+cmake_minimum_required(VERSION 3.22...3.25)
 
 legacy_check()