Switch to Java 21 the branding plugin

Author: BoykoAlex

eclipse-distribution/org.springframework.boot.ide.branding/.classpath

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src/"/>
 	<classpathentry kind="output" path="target/classes"/>

eclipse-distribution/org.springframework.boot.ide.branding/META-INF/MANIFEST.MF

@@ -9,7 +9,7 @@ Require-Bundle: org.eclipse.ui,
  org.eclipse.equinox.p2.ui.sdk,
  org.springsource.ide.eclipse.commons.core,
  org.eclipse.equinox.p2.engine
-Bundle-RequiredExecutionEnvironment: JavaSE-17
+Bundle-RequiredExecutionEnvironment: JavaSE-21
 Bundle-Localization: plugin
 Bundle-ActivationPolicy: lazy
 Import-Package: org.eclipse.core.runtime,