Add ISCSI storage type in agent's json parser

i just tried to run the v1.4 agent on my servers and got the following output:

[info] sending contact request to server0
[info] sending prolog request to server0
[info] running task Inventory
[info] New inventory from pve-enc0bl01-2022-08-02-12-13-36 for server0 (tag=enc0bl01)
[error] [http client] communication error: 500 Internal Server Error
[error] [http client] server error: JSON does not validate. Violations:
"ISCSI" does not match to ^(SCSI|HDC|IDE|USB|1394|SATA|SAS|ATAPI)$ at #->properties:content->properties:storages->items[1]:1->properties:interface

that makes sense as some of my lvm volumes are hosted on a HPE MSA2040, which is accessible through ISCSI

I think that ISCSI is a type of storage worthy of being counted in the standard types

please add it :-)