core: add more strict_types

Signed-off-by: J0WI <J0WI@users.noreply.github.com>

core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright 2018 Morris Jobke <hey@morrisjobke.de>
  *

core/BackgroundJobs/CheckForUserCertificates.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright 2020 Morris Jobke <hey@morrisjobke.de>
  *
@@ -49,7 +52,7 @@ class CheckForUserCertificates extends QueuedJob {
 	/**
 	 * Checks all user directories for old user uploaded certificates
 	 */
-	public function run($arguments) {
+	public function run($arguments): void {
 		$uploadList = [];
 		$this->userManager->callForSeenUsers(function (IUser $user) use (&$uploadList) {
 			$userId = $user->getUID();

core/BackgroundJobs/CleanupLoginFlowV2.php

@@ -42,7 +42,7 @@ class CleanupLoginFlowV2 extends TimedJob {
 		$this->setInterval(3600);
 	}
 
-	protected function run($argument) {
+	protected function run($argument): void {
 		$this->loginFlowV2Mapper->cleanup();
 	}
 }

core/register_command.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *

core/routes.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *

core/strings.php

@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *