Update Command/ExpireGroupBase: add type declarations

Signed-off-by: Josh <josh.t.richards@gmail.com>

lib/Command/ExpireGroup/ExpireGroupBase.php

@@ -35,14 +35,14 @@ public function __construct() {
 		parent::__construct();
 	}
 
-	protected function configure() {
+	protected function configure(): void {
 		$this
 			->setName('groupfolders:expire')
 			->setDescription('Trigger expiration for files stored in group folders (trash and versions). Currently disabled.');
 		parent::configure();
 	}
 
-	protected function execute(InputInterface $input, OutputInterface $output) {
+	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$output->writeln('<error>groupfolder expiration handling is currently disabled because there is nothing to expire. Enable the "Delete Files" or/and "Versions" app to enable this feature.</error>');
 		return 0;
 	}