fix(instance): correct bootscript architecture field name (scaleway#2115)

Author: scaleway-bot

api/instance/v1/instance_sdk.go

@@ -1234,9 +1234,9 @@ type Bootscript struct {
 // Title: bootscript title.
 Title string `json:"title"`
 
-// Arch: bootscript architecture.
+// Architecture: bootscript architecture.
 // Default value: unknown_arch
-Arch Arch `json:"arch"`
+Architecture Arch `json:"architecture"`
 
 // Zone: zone in which the bootscript is located.
 Zone scw.Zone `json:"zone"`