In #2072 <https://github.com/apache/logging-log4j2/pull/2072>, I have upgraded `main` to Spring Boot 3 and ported `log4j-spring-cloud-config-client` changes from `2.x`.
Matt, Ralph, you might want to review this, since 1. I needed to add methods you had removed (Spring Boot 3 needs them) 2. `JndiRule` is rewritten (`SimpleNamingContextBuilder` of `spring-test` is removed in Spring Framework 6 packaged with Spring Boot 3)
