feat: add volume format property (#397)

This property was previously missing, although it was already used in
VolumeCreateOpts. It's now a string pointer with common values (ext4 and
xfs) available as string constants.

---------

Co-authored-by: pauhull <[email protected]>
Co-authored-by: Jonas L. <[email protected]>

Author: phm07

hcloud/schema/volume.go

@@ -10,6 +10,7 @@ type Volume struct {
 	Status      string            `json:"status"`
 	Location    Location          `json:"location"`
 	Size        int               `json:"size"`
+	Format      *string           `json:"format"`
 	Protection  VolumeProtection  `json:"protection"`
 	Labels      map[string]string `json:"labels"`
 	LinuxDevice string            `json:"linux_device"`

hcloud/schema_test.go

@@ -662,6 +662,7 @@ func TestVolumeSchema(t *testing.T) {
 		"name": "db-storage",
 		"status": "creating",
 		"server": 2,
+		"format": "xfs",
 		"location": {
 			"id": 1,
 			"name": "fsn1",

hcloud/volume.go

@@ -21,12 +21,18 @@ type Volume struct {
 	Server      *Server
 	Location    *Location
 	Size        int
+	Format      *string
 	Protection  VolumeProtection
 	Labels      map[string]string
 	LinuxDevice string
 	Created     time.Time
 }
 
+const (
+	VolumeFormatExt4 = "ext4"
+	VolumeFormatXFS  = "xfs"
+)
+
 // VolumeProtection represents the protection level of a volume.
 type VolumeProtection struct {
 	Delete bool