ci(fwu): update script to generate FWU metadata version 2

Script is updated to generate FWU metadata version as per the
latest changes in the PSA FWU specification[1].

[1]: https://developer.arm.com/documentation/den0118/latest/

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I264f8f5464398d6ce300f1e70cee665f0c38b3e0
1 file changed