TUF specification has a new version - v1.0.30

[github-actions]

Hey, it seems there's a newer version of the TUF specification - v1.0.30

The version which theupdateframework/rust-tuf states it supports is - v1.0.29

The following is a comparison of what changed between the two versions - Compare v1.0.29 to v1.0.30

Please review the newer version and address the changes.