Missing dependency doctrine/annotations since jms/serializer:3.30.0

[mbaschnitzi]

In version 3.30.0 of jms/serializer the dependency on doctrine/annotations was dropped. (See schmittjoh/serializer#1471)

This causes the parsing of xml to fail because the serializer cannot read the annotations anymore if the project using this library does not explicitly require doctrine/annotations.

This issue could be solved by either depending on doctrine/annotations or by converting the annotations to php attributes.