feat(presets): update java LTS workaround to include v21 (#25175)

lib/config/presets/internal/workarounds.ts

@@ -105,7 +105,7 @@ export const presets: Record<string, Preset> = {
     description: 'Limit Java runtime versions to LTS releases.',
     packageRules: [
       {
-        allowedVersions: '/^(?:8|11|17)(?:\\.|-|$)/',
+        allowedVersions: '/^(?:8|11|17|21)(?:\\.|-|$)/',
         description:
           'Limit Java runtime versions to LTS releases. To receive all major releases add `workarounds:javaLTSVersions` to the `ignorePresets` array.',
         matchDatasources: ['docker', 'java-version'],