Reference OpenTofu support in TF Readme (#3141)

To clarify the state of the world for OpenTofu, we mention that the provider should work with OpenTofu but it isn't tested and should be considered experimental.

README.md

@@ -157,6 +157,10 @@ output "job_url" {
 
 Then run `terraform init` then `terraform apply` to apply the hcl code to your Databricks workspace.
 
+## OpenTofu Support
+
+[OpenTofu](https://opentofu.org/) is an open-source fork of Terraform with the MPL 2.0 license. The Databricks Terraform provider should be compatible with OpenTofu, but this integration is not actively tested and should be considered experimental. Please raise a Github issue if you find any incompatibility.
+
 ## Switching from `databrickslabs` to `databricks` namespace
 
 To make Databricks Terraform Provider generally available, we've moved it from [https://github.com/databrickslabs](https://github.com/databrickslabs) to [https://github.com/databricks](https://github.com/databricks). We've worked closely with the Terraform Registry team at Hashicorp to ensure a smooth migration. Existing terraform deployments continue to work as expected without any action from your side. We ask you to replace `databrickslabs/databricks` with `databricks/databricks` in all your `.tf` files.