Release v20.62.6

Fixed

• Fixed an unbounded recursion that overflowed the stack and terminated the process when deserializing a read model with an interface- or abstract-typed polymorphic member (a [DerivedType] hierarchy) from MongoDB. The derived-type discriminator convention is now registered for the concrete derived types' class maps as well, and an unresolvable polymorphic value now surfaces as a catchable exception instead of crashing the process.