chore: ran sync-tidy

Author: s-inter

services/vpn/go.mod

@@ -2,7 +2,10 @@ module github.com/stackitcloud/stackit-sdk-go/services/vpn
 
 go 1.25
 
-require github.com/stackitcloud/stackit-sdk-go/core v0.26.0
+require (
+	github.com/google/go-cmp v0.7.0
+	github.com/stackitcloud/stackit-sdk-go/core v0.26.0
+)
 
 require (
 	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect