make sure sass_api pubspec follows the root pubspec

Author: Goodwine

pkg/sass_api/pubspec.yaml

@@ -13,7 +13,7 @@ dependencies:
   sass: 1.93.2
 
 dev_dependencies:
-  dartdoc: ^8.0.14
+  dartdoc: ">=8.0.14 <10.0.0"
 
 dependency_overrides:
   sass: { path: ../.. }