Add a workflow that runs terraform plan on PRs

.github/workflows/pr-plan.yml

@@ -0,0 +1,41 @@
+name: 'Terraform Plan'
+
+permissions:
+  contents: read
+  id-token: write
+
+on:
+  workflow_dispatch:
+  pull_request:
+    branches:
+      - 'main'
+      - mainline
+
+jobs:
+  terraform:
+    name: 'Terraform Plan'
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: 'Checkout Repository'
+      uses: actions/checkout@v3
+
+    - name: Configure AWS Credentials
+      uses: aws-actions/configure-aws-credentials@v4
+      with:
+        role-to-assume: "arn:aws:iam::${{ secrets.AWS_ACCOUNT_ID }}:role/${{ secrets.AWS_ROLE_NAME }}"
+        aws-region: us-west-2
+
+    - name: 'Setup Terraform'
+      uses: hashicorp/setup-terraform@v1
+      with:
+        terraform_version: '1.4.6' # Replace with your desired version
+
+    - name: 'Terraform Init'
+      id: init
+      run: terraform init
+
+    - name: 'Terraform Plan'
+      id: plan
+      run: terraform plan
+      # If the Terraform plan fails, the workflow will fail and stop executing further steps.