Support opentofu (#29)

Author: goruha

README.yaml

@@ -73,6 +73,7 @@ usage: |
   integrations:
     github:
       gitops:
+        opentofu-version: 1.7.3
         terraform-version: 1.5.2
         infracost-enabled: false
         artifact-storage:
@@ -91,6 +92,35 @@ usage: |
   > [!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.

action.yml

@@ -72,9 +72,30 @@ runs:
       shell: bash
       id: config
       run: |-
+        echo "opentofu-version=$(atmos describe config -f json | jq -r '.integrations.github.gitops["opentofu-version"]')" >> $GITHUB_OUTPUT        
+        echo "terraform-version=$(atmos describe config -f json | jq -r '.integrations.github.gitops["terraform-version"]')" >> $GITHUB_OUTPUT        
         echo "group-by=$(atmos describe config -f json | jq -r '.integrations.github.gitops.matrix["group-by"]')" >> $GITHUB_OUTPUT
         echo "sort-by=$(atmos describe config -f json | jq -r '.integrations.github.gitops.matrix["sort-by"]')" >> $GITHUB_OUTPUT        
 
+    - name: Install Terraform
+      if: ${{ steps.config.outputs.terraform-version != '' && steps.config.outputs.terraform-version != 'null' }}
+      uses: hashicorp/setup-terraform@v3
+      with:
+        terraform_version: ${{ steps.config.outputs.terraform-version }}
+        terraform_wrapper: false
+
+    - name: Install OpenTofu
+      if: ${{ steps.config.outputs.opentofu-version != '' && steps.config.outputs.opentofu-version != 'null' }}
+      uses: opentofu/setup-opentofu@v1
+      with:
+        tofu_version: ${{ steps.config.outputs.opentofu-version }}
+        tofu_wrapper: false
+
+    - name: Install Node
+      uses: actions/setup-node@v4
+      with:
+        node-version: 20
+
     - name: Filter Components
       id: selected-components
       shell: bash