Deserialization of untrusted data in the Gremlin graph-import path in Amazon Neptune

Deserialization of untrusted data in the Gremlin graph data import component in Amazon Neptune engine might allow an authenticated remote actor with standard database permissions to execute arbitrary code and access internal service credentials. To remediate this issue, users not enrolled in auto-update should upgrade to Amazon Neptune engine version 1.5.0.0.(Backports to 1.4.8.1 and 1.4.7.1)