Jenkins DSL: Add JDK 20 and 21 to Test-Environment job

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1911584 13f79535-47bb-0310-9956-ffa450edef68

jenkins/create_jobs.groovy

@@ -632,6 +632,8 @@ Unfortunately we often see builds break because of changes/new machines...''')
                 'jdk_17_latest',
                 'jdk_18_latest',
                 'jdk_19_latest',
+                'jdk_20_latest',
+                'jdk_21_latest',
                 'adoptopenjdk_hotspot_8u282',
                 'ibmjdk_1.8.0_261'
         )