Bump shared library version to 6.4.2 (#4600)

Signed-off-by: Rishabh Singh <sngri@amazon.com>

Author: rishabh6788

jenkins/gradle/gradle-check.jenkinsfile

@@ -7,7 +7,7 @@
  * compatible open source license.
  */
 
-lib = library(identifier: 'jenkins@6.4.0', retriever: modernSCM([
+lib = library(identifier: 'jenkins@6.4.2', retriever: modernSCM([
     $class: 'GitSCMSource',
     remote: 'https://github.com/opensearch-project/opensearch-build-libraries.git',
 ]))