40c357bbc5
`CommitGPGSignature` was originally made to store information about a commit's GPG signature. Nowadays, it is used to store information about SSH signatures too, and not just commit signatures, but tag signatures too. As such, rename it to `ObjectSignature`, because that describes what it does a whole lot better. Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>