Resolve #3321416 by HongPong. Re-add ctools 3.x + 4.x as allowed in composer

composer.json

@@ -18,7 +18,7 @@
     "minimum-stability": "dev",
     "require": {
         "drupal/migrate_plus": "~6.0",
-        "drupal/ctools": "~4.0"
+        "drupal/ctools": "^3 || ^4"
     },
     "require-dev": {
         "drupal/migrate_tools": "~6.0"