Attacker-controlled parameter can cause denial of service in hamba avro

Hamba avro is a go lang encoder/decoder implementation of the avro codec specification. In affected versions a well-crafted string passed to avro's `github.com/hamba/avro/v2.Unmarshal()` can throw a `fatal error: runtime: out of memory` which is unrecoverable and can cause denial of service of the consumer of avro. The root cause of the issue is that avro uses part of the input to `Unmarshal()` to determine the size when creating a new slice and hence an attacker may consume arbitrary amounts of memory which in turn may cause the application to crash. This issue has been addressed in commit `b4a402f4` which has been included in release version `2.13.0`. Users are advised to upgrade. There are no known workarounds for this vulnerability.