Denial of Service in Tink-cc

There exists a Denial of service vulnerability in Tink-cc in versions prior to 2.1.3.  * An adversary can crash binaries using the crypto::tink::JsonKeysetReader in tink-cc by providing an input that is not an encoded JSON object, but still a valid encoded JSON element, for example a number or an array. This will crash as Tink just assumes any valid JSON input will contain an object. * An adversary can crash binaries using the crypto::tink::JsonKeysetReader in tink-cc by providing an input containing many nested JSON objects. This may result in a stack overflow. We recommend upgrading to version 2.1.3 or above