The previously used uuid 4f68bce3-e8cd-4db1-96e7-fbcaf984b709 is valid
for x86_64 root partitions, which resulted in the dev container not
working with systemd-nspawn on aarch64. systemd-nspawn fails with:
No suitable root partition found in image
Change the partition uuid to the architecture agnostic one documented
in the man page:
A GUID partition table (GPT) with a single partition of type 0fc63daf-8483-4772-8e79-3d69d8477de4.
This makes systemd-nspawn happy on aarch64.
Signed-off-by: Jeremi Piotrowski <jpiotrowski@microsoft.com>