mkosi: update debian commit reference

mkosi: update debian commit reference

* 08eb5e1eff Set tty device node mode to 0600
* e3955d1ca2 initramfs-tools: copy hwdb.bin to initramfs
* aff03b8933 d/rules: fix bpftool path discovery on ubuntu
* cab4f15666 Update changelog for 257.3-1 release
* 9bfeffe2a3 autopkgtest: fix mkosi config section
* 44487bfe02 ukify: depend on python3-zstandard and recommend python3-lz4
* 0a20294f18 d/rules: adjust vmlinux.h path for Ubuntu
* 94fa0939ed Drop fallback for missing linux-bpf-dev package
* b0b75e3f4b systemd-boot: check that bootvar really points to sd-boot
* 464453cbd6 systemd-boot: fix creating bootvar on arm64
* ce4a878ef7 systemd-boot: warn if efibootmgr is not installed
* cce6971f68 Install new udev rule for hidraw
* 0c483fbd26 d/t/control: do not pull in gdm3 on loong64
* 52451a0c14 d/t/control: depend on debian-archive-keyring and ubuntu-keyring