Bump io.etcd:jetcd-core from 0.3.0 to 0.8.4

Bumps [io.etcd:jetcd-core](https://github.com/etcd-io/jetcd) from 0.3.0 to 0.8.4.
- [Release notes](https://github.com/etcd-io/jetcd/releases)
- [Changelog](https://github.com/etcd-io/jetcd/blob/main/CHANGELOG.md)
- [Commits](https://github.com/etcd-io/jetcd/commits)

---
updated-dependencies:
- dependency-name: io.etcd:jetcd-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

eventmesh-meta/eventmesh-meta-etcd/build.gradle

@@ -16,7 +16,7 @@
  */
 
 dependencies {
-    implementation ("io.etcd:jetcd-core:0.3.0")
+    implementation ("io.etcd:jetcd-core:0.8.4")
     implementation project(":eventmesh-meta:eventmesh-meta-api")
     implementation project(":eventmesh-common")
     testImplementation "org.mockito:mockito-core"