Add support for Jackson 3

[fmbenhassine]

Following Spring Framework 7 (see spring-projects/spring-framework#33798), Spring Batch should support Jackson 3 by default.

This means Jackson2ExecutionContextStringSerializer should be renamed (by removing the version number from the name) and updated to Jackson 3. The Jackson 2 based serializer will be supported for v5.2.

[HyunSangHan]

I’m interested in contributing to this feature. Since Jackson 3 is currently only available as an RC version, would it be better to wait until the official release before starting this work?

Here’s my understanding of the tasks involved:

1. Add a Jackson 3 dependency to spring-batch-core/pom.xml.
2. Implement a new ExecutionContextSerializer to JacksonExecutionContextStringSerializer based on Jackson 3.
3. Create JacksonExecutionContextStringSerializerTests to verify the implementation.
4. Mark the existing Jackson2ExecutionContextStringSerializer with the @Deprecated annotation. For backward compatibility, we can keep it until v5.2 and consider removing it afterwards.
5. Update the existing usages of Jackson2ExecutionContextStringSerializer to depend on JacksonExecutionContextStringSerializer.

If this plan sounds good to you, I’d be happy to contribute.