fix(fetch-terraform-output): default environment_name to ref_name on push events

github.base_ref is empty on push events, causing the job to run without
a GitHub environment. Use the same fallback pattern as terraform_workspace:
base_ref || ref_name.

Author: cpetit-sw

.github/workflows/fetch-terraform-output.yml

@@ -23,7 +23,7 @@ on:
       environment_name:
         required: false
         type: string
-        default: ${{ github.base_ref }}
+        default: ${{ github.base_ref || github.ref_name }}
       terraform_workspace:
         required: false
         type: string