Fix update-credits.sh
Fix update-credits.sh

The script would insert an additional newline
before the Firecracker contributors.

Signed-off-by: Diana Popa <4240422768c1b315e51818a074064501037757cd@amazon.com>
Signed-off-by: Pablo Barbáchano <2db534d6341c8fef7c3f3d380b64f9115b9d896d@amazon.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker