Add 2-5 zfs-release RPMs, including Fedora 40 (#90)

- Add 2-5 zfs-release RPMs for F38-40
- Sign with SHA512 key

Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>

Author: tonyhutter