silverstripe/graphql Denial of Service vulnerability

`silverstripe/graphql` serves Silverstripe data as GraphQL representations. In versions 4.2.2 and 4.1.1, an attacker could use a specially crafted graphql query to execute a denial of service attack against a website which has a publicly exposed graphql endpoint. This mostly affects websites with particularly large/complex graphql schemas. Users should upgrade to `silverstripe/graphql` 4.2.3 or 4.1.2 to remedy the vulnerability.