How to programatically register a 3rd party serializer (Flink 1.20)

[Jean-Marc Paulin]

I am trying to use 3rd party serializers as per
https://nightlies.apache.org/flink/flink-docs-release-1.20/docs/dev/datastream/fault-tolerance/serialization/third_party_serializers/

but the code sample does not compile
```
Configuration config = new Configuration();
// register the class of the serializer as serializer for a type
config.set(PipelineOptions.SERIALIZATION_CONFIG,
    "[org.example.MyCustomType: {type: kryo, kryo-type: registered, class:
org.example.MyCustomSerializer}]");
```
because the expected parameter is a list of strings. I can do

```
config.set(PipelineOptions.SERIALIZATION_CONFIG, List.of(
    "org.example.MyCustomType: {type: kryo, kryo-type: registered, class:
org.example.MyCustomSerializer}"));
```

But is it correct? I am concerned about the "[ ]" that denotes a collection
in yaml/json.

Thanks

JM