Remove unused schema and fix action.yml typo

Author: jormundur00

.github/actions/detect-file-changes/action.yml

@@ -13,5 +13,5 @@ runs:
   using: "node20"
   main: "detect-file-changes.js"
 outputs:
-  changes_detected:
+  changed:
     description: "Returns `true` if any changed file matches the specified patterns, `false` otherwise."