Bump org.apache.logging.log4j:log4j-jpl in /data-prepper-core

Bumps org.apache.logging.log4j:log4j-jpl from 2.20.0 to 2.21.1.

---
updated-dependencies:
- dependency-name: org.apache.logging.log4j:log4j-jpl
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

data-prepper-core/build.gradle

@@ -39,7 +39,7 @@ dependencies {
         exclude group: 'commons-logging', module: 'commons-logging'
     }
     implementation 'software.amazon.cloudwatchlogs:aws-embedded-metrics:2.0.0-beta-1'
-    testImplementation 'org.apache.logging.log4j:log4j-jpl:2.20.0'
+    testImplementation 'org.apache.logging.log4j:log4j-jpl:2.21.1'
     testImplementation testLibs.spring.test
     implementation libs.armeria.core
     implementation libs.armeria.grpc