osbuild2: ostree options for the fstab stage

osbuild, since version 30, supports the ostree deployments for the
fstab stage.

Co-Developed-by: Achilleas Koutsou <achilleas@koutsou.net>
Co-Developed-by: Christian Kellner <christian@kellner.me>

internal/osbuild2/fstab_stage.go

@@ -7,10 +7,16 @@ package osbuild2
 // are set to their defaults (if possible).
 type FSTabStageOptions struct {
 	FileSystems []*FSTabEntry `json:"filesystems"`
+
+	OSTree *OSTreeFstab `json:"ostree,omitempty"`
 }
 
 func (FSTabStageOptions) isStageOptions() {}
 
+type OSTreeFstab struct {
+	Deployment OSTreeDeployment `json:"deployment"`
+}
+
 // NewFSTabStage creates a now FSTabStage object
 func NewFSTabStage(options *FSTabStageOptions) *Stage {
 	return &Stage{