main/postmarketos-initramfs: add 95-dm-notify.rules

device-mapper-2.03.35-r5 is now being built with --enable-udev_sync: https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/107049

This means we must include 95-dm-notify.rules in the initramfs, or else the "cryptsetup luksOpen" command never finishes as the udev sync can't complete.

Fix #4842 (closed)