chore: Update readme for GraphQL spec compability (#6270)

* Update README.md

* Remove duplicate

Co-authored-by: Martin Bonnin <martin@mbonnin.net>

---------

Co-authored-by: Martin Bonnin <martin@mbonnin.net>

Author: calvincestari

README.md

@@ -33,6 +33,8 @@ Because generated types are operation-specific, you can only access data that yo
 
 This library is designed with Android in mind, but you can use it in any Kotlin application, including KMP ([Kotlin Multi Platform](https://kotlinlang.org/docs/multiplatform.html)).
 
+Apollo Kotlin aims to comply with the [Working Draft of the GraphQL specification](https://spec.graphql.org/draft/).
+
 ## 📚 Documentation
 
 All Apollo Kotlin documentation, including caching and helpful recipes, can be found at: <br/>