Update v3-upgrade-guide.md

add links to SDKv1 and Terraform Plugin Framework

docs/guides/v3-upgrade-guide.md

@@ -13,7 +13,7 @@ This guide covers the changes introduced in v3.0.0 of the Helm provider and what
 
 ### Adoption of the Terraform Plugin Framework
 
-The Helm provider has been migrated from the legacy SDKv2 to the Terraform Plugin Framework. This migration introduces structural changes to the schema, affecting nested blocks, attribute names, and how configurations are represented. Users must update their configurations to align with the new framework. Key changes include:
+The Helm provider has been migrated from the legacy [Terraform Plugin SDKv2](https://github.com/hashicorp/terraform-plugin-sdk) to the [Terraform Plugin Framework](https://github.com/hashicorp/terraform-plugin-framework). This migration introduces structural changes to the schema, affecting nested blocks, attribute names, and how configurations are represented. Users must update their configurations to align with the new framework. Key changes include:
 
 - **Blocks to Nested Objects**: Blocks like `kubernetes`, `registry`, and `experiments` are now represented as nested objects.
 - **List Syntax for Nested Attributes**: Attributes like `set`, `set_list`, and `set_sensitive` in `helm_release` and `helm_template` are now lists of nested objects instead of blocks.