--diff flag is useless without -v option

Describe the bug

Hello !

The commands permifrost run <spec-file> --dry --diff
and permifrost run <spec-file> --dry Gives the same result in every situation, it seems that --diff is just adding a + sign before the printing of query.

Steps To Reproduce

Create a spec-file with not granted on server rights, run permifrost run <spec-file> --dry --diff here this is the same result as permifrost run <spec-file> --dry because all rights are new (not on the server).

Manually run one of the granting on the server, so if I understood corrcetly the --diff flag should show the same lines but without the + before the query used to grant the new manually granted right. if you run permifrost run <spec-file> --dry --diff you will not see the manually added right but only new rights with a + and a PENDING state

Expected behavior

permifrost run <spec-file> --dry --diff should show already granted rights on the server. (as permifrost -v run <spec-file> --dry --diff is doing)

Screenshots and log output

If applicable, add screenshots or log output to help explain your problem.

The output of permifrost --version:

permifrost, version 0.14.0

Macos Python 3.9.1

Additional context

I think it is due to this line https://gitlab.com/gitlab-data/permifrost/-/blob/master/src/permifrost/cli/permissions.py#L191 In my understanding we are showing only NOT already granted queries unless the -v option is set.

I think --diff should imply -v to show the skipped queries however it is a little misleading I might have done something wrong but this is the --diff behaviour I understood from the readme.

I think this below would be good, or if no dev is wanted at least upd the readme.

This :

    if ctx.parent.params.get("verbose", 0) >= 1:
        print_skipped = True

Could be replaced by

    if ctx.parent.params.get("verbose", 0) >= 1 or diff is True:
        print_skipped = True

Thanks a lot for the library 😄