v2.20.6

Changed

• [closes #43198] Bugfix: When printing a Return message the z value is displayed correctly
• [refs #43331] Disable Python build for Windows external project (install target is not functional) => Please use PIP package
• [refs #43331] Add missing cmake_minimum_required to CMake external example which is requried for recent CMake versions
• [refs #43331] Improve Windows build guide
• Pin debian testing package to bullseye as bookworm is not yet supported