terraform-enterprise: mark otf dead

Signed-off-by: Rui Chen <rui@chenrui.dev>

README.md

@@ -465,7 +465,7 @@ For more Community Modules not listed here please see the [Terraform Module Regi
 
 ## Self-hosted Terraform Platforms
 
-- [OTF](https://github.com/leg100/otf) - Open Terraforming Framework, an open source alternative to Terraform Enterprise with full Terraform CLI integration.
+- [OTF](https://github.com/leg100/otf) - Open Terraforming Framework, an open source alternative to Terraform Enterprise with full Terraform CLI integration. :skull:
 - [Terrakube](https://docs.terrakube.io) - Open Source alternative to Terraform Enterprise with private registry, remote state, custom flows, scheduled workspaces, and visual states.
 - [Digger](https://digger.dev) - Open Source Alternative to Terraform Cloud - Run Terraform plan & apply jobs in your CI.
 - [cloud-concierge](https://github.com/dragondrop-cloud/cloud-concierge) - Open Source, codify unmanaged resources as Terraform, detect drift, and cloud cost and security analysis, delivered as a Pull Request.