Update Build SWT Natives launch to Java 21

Eclipse SWT now uses Tycho 5.x which means we need to run Maven with
Java 21

Author: jonahgraham

bundles/org.eclipse.swt/Build-SWT-native-binaries-for-running-platform.launch

@@ -20,6 +20,6 @@
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_ATTR_USE_ARGFILE" value="false"/>
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_SHOW_CODEDETAILS_IN_EXCEPTION_MESSAGES" value="true"/>
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_USE_CLASSPATH_ONLY_JAR" value="false"/>
-    <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17/"/>
+    <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21/"/>
     <stringAttribute key="org.eclipse.jdt.launching.WORKING_DIRECTORY" value="${git_work_tree:/org.eclipse.swt}/binaries/org.eclipse.swt.${target.ws}.${target.os}.${target.arch}"/>
 </launchConfiguration>