Add a return message for app updates trough occ

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

Handle single and all apps

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

Rewrite logic

Fix psalm

Fix psalm

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

core/Command/App/Update.php

@@ -77,6 +77,7 @@ class Update extends Command {
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$singleAppId = $input->getArgument('app-id');
+		$updateFound = false;
 
 		if ($singleAppId) {
 			$apps = [$singleAppId];
@@ -97,6 +98,7 @@ class Update extends Command {
 		foreach ($apps as $appId) {
 			$newVersion = $this->installer->isUpdateAvailable($appId, $input->getOption('allow-unstable'));
 			if ($newVersion) {
+				$updateFound = true;
 				$output->writeln($appId . ' new version available: ' . $newVersion);
 
 				if (!$input->getOption('showonly')) {
@@ -122,6 +124,14 @@ class Update extends Command {
 			}
 		}
 
+		if (!$updateFound) {
+			if ($singleAppId) {
+				$output->writeln($singleAppId . ' is up-to-date or no updates could be found');
+			} else {
+				$output->writeln('All apps are up-to-date or no updates could be found');
+			}
+		}
+
 		return $return;
 	}
 }