[proxmox] add proxmox builder alias

Adds an alias for `proxmox` that points to proxmox-iso builder for
backwards compatibility

builder/proxmox/builder.go

@@ -0,0 +1,7 @@
+package proxmox
+
+import (
+	"github.com/hashicorp/packer/builder/proxmox/iso"
+)
+
+type Builder  = proxmoxiso.Builder

command/plugin.go

@@ -48,6 +48,7 @@ import (
 	parallelsisobuilder "github.com/hashicorp/packer/builder/parallels/iso"
 	parallelspvmbuilder "github.com/hashicorp/packer/builder/parallels/pvm"
 	profitbricksbuilder "github.com/hashicorp/packer/builder/profitbricks"
+	proxmoxbuilder "github.com/hashicorp/packer/builder/proxmox"
 	proxmoxclonebuilder "github.com/hashicorp/packer/builder/proxmox/clone"
 	proxmoxisobuilder "github.com/hashicorp/packer/builder/proxmox/iso"
 	qemubuilder "github.com/hashicorp/packer/builder/qemu"
@@ -146,6 +147,7 @@ var Builders = map[string]packer.Builder{
 	"parallels-iso":       new(parallelsisobuilder.Builder),
 	"parallels-pvm":       new(parallelspvmbuilder.Builder),
 	"profitbricks":        new(profitbricksbuilder.Builder),
+	"proxmox":             new(proxmoxbuilder.Builder),
 	"proxmox-clone":       new(proxmoxclonebuilder.Builder),
 	"proxmox-iso":         new(proxmoxisobuilder.Builder),
 	"qemu":                new(qemubuilder.Builder),