chore: update README.md

Author: actions-user

README.md

@@ -79,6 +79,7 @@ The config should have the following structure:
 integrations:
   github:
     gitops:
+      opentofu-version: 1.7.3
       terraform-version: 1.5.2
       infracost-enabled: false
       artifact-storage:
@@ -97,6 +98,35 @@ integrations:
 > [!IMPORTANT]
 > **Please note!** This GitHub Action only works with `atmos >= 1.63.0`. If you are using `atmos < 1.63.0` please use `v1` version of this action.    
 
+### Support OpenTofu
+
+This action supports [OpenTofu](https://opentofu.org/).
+
+> [!IMPORTANT]
+> **Please note!** OpenTofu supported by Atmos `>= 1.73.0`.
+> For details [read](https://atmos.tools/core-concepts/projects/configuration/opentofu/)
+
+To enable OpenTofu add the following settings to `atmos.yaml`
+  * Set the `opentofu-version` in the `atmos.yaml` to the desired version
+  * Set `components.terraform.command` to `tofu`
+
+#### Example
+
+```yaml
+
+components:
+  terraform:
+    command: tofu
+
+...
+
+integrations:
+  github:
+    gitops:
+      opentofu-version: 1.7.3
+      ...
+```    
+
 ### GitHub Actions Workflow Example
 
 In following GitHub workflow example first job will filter components that have settings `github.actions_enabled: true` and then in following job `stack_slug` will be printed to stdout.