fix: add deprecation notice for the vpn_gateways input

[imprateeksh]

Description

This PR is to include the documentation about the deprecation of in-module VPN gateway provisioning in the Landing Zone VPC module mentioning about planned removal in upcoming release. The intention is to remove the direct usage of resource in root module and consume site to site VPN module.

Release required?

• No release
• Patch release (x.x.X)
• Minor release (x.X.x)
• Major release (X.x.x)

Release notes content

• Resource address changes:
  Root‑level ibm_is_vpn_gateway resource will be refactored into the vpn_gateways module. Once this is done, users must migrate state using terraform state mv command to avoid recreation of ibm_is_vpn_gateway resource.

  Example:

    terraform state mv \
      'module.slz_vpc.ibm_is_vpn_gateway.vpn_gateway["vpg1"]' \
      'module.slz_vpc.module.vpn_gateways["vpg1"].ibm_is_vpn_gateway.vpn_gateway[0]'

  For more details about the migration of vpn gateway resources, please refer the migration guide.

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• If relevant, a test for the change is included or updated with this PR.
• If relevant, documentation for the change is included or updated with this PR.

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[imprateeksh]

/run pipeline

[imprateeksh]

Marked this as major release as per the comment given in the internal issue i.e. getting the new major version released with a migration guide.

[imprateeksh]

Before migrating state - Recreation of resource can be seen

After Migration : Resource recreation is not happening

[ocofaigh]

left some comments

[imprateeksh]

/run pipeline

[imprateeksh]

/run pipeline

[imprateeksh]

/run pipeline

[ocofaigh]

@imprateeksh You didn't add the ignore to all tests. The TestFullyConfigurableWithFlowLogs test failed with:

        	Messages:   	Resource(s) identified to be destroyed 
        	            	Name: deprecation_warning
        	            	Address: module.vpc.terraform_data.deprecation_warning[0]
        	            	Actions: [delete create]
        	            	DIFF:
        	            	  Before: 
        	            		{"id":"574c7dfe-7846-a7a8-0a22-39e4fa5e2f08","triggers_replace":{"always_run":"2026-01-16T21:31:24Z"}}
        	            	  After: 
        	            		{"triggers_replace":{}}

[imprateeksh]

/run pipeline

[imprateeksh]

PR failures are now seen with different errors:

• TestFullyConfigurableWithFlowLogs - Failed to get best VPC region
• TestRunUpgradeFullyConfigurable - Failed to get best VPC region
• TestRunHubAndSpokeDelegatedExample - timeout while waiting for state to become ', detached'

[ocofaigh]

@imprateeksh There is a bug (here) in the code - the VPC region function should not be failing the tests. @Khuzaima05 is going to fix it in #1082

[maheshwarishikha]

I am seeing one deprecate notice related failure in other repo - terraform-ibm-modules/terraform-ibm-observability-da#577 (comment)

Is something missing here?

[ocofaigh]

@maheshwarishikha yes, see terraform-ibm-modules/terraform-ibm-observability-da#577 (comment)

[imprateeksh]

/run pipeline

[ocofaigh]

Failed with:

         2026/01/20 11:46:10 Terraform destroy | Error: ---
         2026/01/20 11:46:10 Terraform destroy | id: terraform-c907de16
         2026/01/20 11:46:10 Terraform destroy | summary: 'isWaitForSubnetDeleted failed: timeout while waiting for state to become
         2026/01/20 11:46:10 Terraform destroy |   ''done, '' (last state: ''deleting'', timeout: 10m0s)'
         2026/01/20 11:46:10 Terraform destroy | severity: error
         2026/01/20 11:46:10 Terraform destroy | resource: ibm_is_subnet
         2026/01/20 11:46:10 Terraform destroy | operation: delete
         2026/01/20 11:46:10 Terraform destroy | component:
         2026/01/20 11:46:10 Terraform destroy |   name: github.com/IBM-Cloud/terraform-provider-ibm
         2026/01/20 11:46:10 Terraform destroy |   version: 1.87.1
         2026/01/20 11:46:10 Terraform destroy | ---

Unrelated to changes in this Pr, so retrying..

[ocofaigh]

/run pipeline

[terraform-ibm-modules-ops]

🎉 This PR is included in version 8.11.2 🎉

The release is available on:

• GitHub release
• v8.11.2

Your semantic-release bot 📦🚀

[ocofaigh]

@imprateeksh It seems you missed adding this to the IgnoreDestroy:

        	Test:       	TestRunUpgradeFullyConfigurable
        	Messages:   	Resource(s) identified to be destroyed 
        	            	Name: deprecation_warning
        	            	Address: module.vpc.terraform_data.deprecation_warning[0]
        	            	Actions: [delete create]
        	            	DIFF:
        	            	  Before: 
        	            		{"id":"23c3f4a1-5028-f353-8e0a-ee93fec98fe2","triggers_replace":{"always_run":"2026-01-21T17:33:33Z"}}
        	            	  After: 
        	            		{"triggers_replace":{}}

fixed in #1113