fix: update cvm unit test image (#1265)

Co-authored-by: mikatong <mikatong@tencent.com>

Author: tongyiming

tencentcloud/resource_tc_instance_test.go

@@ -711,7 +711,7 @@ const testAccTencentCloudInstanceWithDataDisk = defaultInstanceVariable + `
 resource "tencentcloud_instance" "foo" {
   instance_name     = var.instance_name
   availability_zone = var.availability_cvm_zone
-  image_id          = data.tencentcloud_images.default.images.1.image_id
+  image_id          = data.tencentcloud_images.default.images.0.image_id
   instance_type     = data.tencentcloud_instance_types.default.instance_types.0.instance_type
 
   system_disk_type = "CLOUD_PREMIUM"
@@ -740,7 +740,7 @@ const testAccTencentCloudInstanceWithDataDiskUpdate = defaultInstanceVariable +
 resource "tencentcloud_instance" "foo" {
   instance_name     = var.instance_name
   availability_zone = var.availability_cvm_zone
-  image_id          = data.tencentcloud_images.default.images.1.image_id
+  image_id          = data.tencentcloud_images.default.images.0.image_id
   instance_type     = data.tencentcloud_instance_types.default.instance_types.0.instance_type
 
   system_disk_type = "CLOUD_PREMIUM"