use github output

.github/workflows/update_dbt_marts_schema_changelog.yml

@@ -49,16 +49,21 @@ jobs:
           echo "$output" > changelog/dbt_marts.md
 
       - name: Commit changes
+        id: commit_changes
         run: |
           git add changelog/dbt_marts.md
           if git commit -m "Update changelog for DBT marts"; then
             echo "Changes committed."
-            echo "::set-output name=changes_committed::true"
+            echo "changes_committed=true" >> $GITHUB_OUTPUT
           else
             echo "No changes to commit."
-            echo "::set-output name=changes_committed::false"
+            echo "changes_committed=false" >> $GITHUB_OUTPUT
           fi
 
+      - name: Use that secret output (protected by a mask)
+        run: |
+          echo "the secret number is ${{ steps.commit_changes.outputs.changes_committed }}"
+
       - name: Push branch
         if: steps.commit_changes.outputs.changes_committed == 'true'
         run: |