Fix zone identifier regex to allow single-letter zone names

Co-authored-by: pavel <[email protected]>

Author: cursoragent

fwprovider/cluster/sdn/zone/resource_generic.go

@@ -97,7 +97,7 @@ func genericAttributesWith(extraAttributes ...map[string]schema.Attribute) map[s
 			Validators: []validator.String{
 				// https://github.com/proxmox/pve-network/blob/faaf96a8378a3e41065018562c09c3de0aa434f5/src/PVE/Network/SDN/Zones/Plugin.pm#L34
 				stringvalidator.RegexMatches(
-					regexp.MustCompile(`^[A-Za-z][A-Za-z0-9]*[A-Za-z0-9]$`),
+					regexp.MustCompile(`^[A-Za-z][A-Za-z0-9]*$`),
 					"must be a valid zone identifier",
 				),
 				stringvalidator.LengthAtMost(8),