ci: use Debian Bookworm (GCC 12) for win64 job

Co-authored-by: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>

ci/test/00_setup_env_win64.sh

@@ -7,7 +7,7 @@
 export LC_ALL=C.UTF-8
 
 export CONTAINER_NAME=ci_win64
-export CI_IMAGE_NAME_TAG="docker.io/amd64/ubuntu:22.04"  # Check that Jammy can cross-compile to win64
+export CI_IMAGE_NAME_TAG="docker.io/amd64/debian:bookworm"  # Check that https://packages.debian.org/bookworm/g++-mingw-w64-x86-64-posix (version 12.2, similar to guix) can cross-compile
 export HOST=x86_64-w64-mingw32
 export DPKG_ADD_ARCH="i386"
 export PACKAGES="nsis g++-mingw-w64-x86-64-posix wine-binfmt wine64 wine32 file"