doc: add breaking changes strategy for Terraform (#1431)

* Docs: add breaking changes strategy for Terraform

* fix: style

* fix: style and simplification

Author: wtrocki

CONTRIBUTING.md

@@ -291,6 +291,7 @@ Examples:
 Most of the new features of the provider are using [atlas-sdk](https://github.com/mongodb/atlas-sdk-go)
 SDK is updated automatically, tracking all new Atlas features.
 
+
 ### Updating Atlas SDK 
 
 To update Atlas SDK run:
@@ -299,6 +300,15 @@ To update Atlas SDK run:
 make update-atlas-sdk
 ```
 
-> NOTE: Update mechanism is only needed for major releases. Any other releases will be supported by dependabot.
+> NOTE: The update mechanism is only needed for major releases. Any other releases will be supported by dependabot.
 
 > NOTE: Command can make import changes to +500 files. Please make sure that you perform update on main branch without any uncommited changes.
+
+### SDK Major Release Update Procedure
+
+1. If the SDK update doesn’t cause any compilation issues create a new SDK update PR
+   1. Review [API Changelog](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/changelog) for any deprecated fields and breaking changes.
+2. For SDK updates introducing compilation issues without graceful workaround
+   1. Use the previous major version of the SDK (including the old client) for the affected resource
+   1. Create an issue to identify the root cause and mitigation paths based on changelog information  
+   2. If applicable: Make required notice/update to the end users based on the plan.