Enable provision option only on main (#79)

Author: mehr74

.github/workflows/terraform.yaml

@@ -16,6 +16,10 @@ on:
       aws-iam-role-arn:
         required: true
         type: string
+      provision-on-main:
+        required: false
+        type: boolean
+        default: true
     secrets:
       github-token:
         description: Token to download Terraform modules from GitHub
@@ -45,7 +49,7 @@ jobs:
         run: terraform fmt -check
 
   provision:
-    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
+    if: ${{ inputs.provision-on-main && github.ref == 'refs/heads/main' }}
     needs: check
     runs-on: ubuntu-latest
     steps: