* [maven-release-plugin] prepare release v8.4.0

* [maven-release-plugin] prepare for next development iteration

logback -> log4j

Fix that the dynamic configuration is deleted on the server side but does not take effect on the agent. (#6255)
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

Fix Java.lang.ClassFormatError: Duplicate interface name "org/apache/skywalking/apm/agent/core/plugin/interceptor/enhance/EnhancedInstance" (#6173)

https://lists.apache.org/thread.html/r4f67a7ed880a493e4e82bd2e9a0c26a6e43c37bbfcdaebe7b1a340dc%40%3Cdev.skywalking.apache.org%3E

* Fix bug that rocketmq-plugin set the wrong tag.

* Update CHANGES.md
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

Fix DataCarrier's `org.apache.skywalking.apm.commons.datacarrier.buffer.Buffer` implementation isn't activated in `IF_POSSIBLE` mode. (#6048)

Trace method(clearScrollAsync) for elasticsearch-6.x-plugin and polishing elasticsearch-6.x-scenario. (#6031)

* Polish elasticsearch-6.x-scenario.

Add interceptors of method(analyze, searchScroll, clearScroll, searchTemplate and deleteByQuery) for elasticsearch-6.x-plugin. (#5962)

* add null conditional operators on these 3 files . To aviod some agent exception of Oracle jdbc.

* Add a line in Java Agent section of CHANGES.md file
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Fix jdk-http and okhttp-3.x did not overwrite the old trace header.

* Update CHANGES.md.

* [maven-release-plugin] prepare release v8.3.0

* [maven-release-plugin] prepare for next development iteration

* Fix okhttp-3.x and async-http-client-2.x did not overwrite the old trace header.

* support spring-kafka 1.3.x and add test

* add spring-kafka-1.3.x-scenario to github workflow

* change kafka-plugin FAQ

* add supported versions

* update CHANGES.md