Bump phpunit and fix CI

Signed-off-by: Julius Härtl <jus@bitgrid.net>

tests/unit/Cron/ScheduledNoificationsTest.php

@@ -18,7 +18,7 @@
  *
  *  You should have received a copy of the GNU Affero General Public License
  *  along with this program. If not, see <http://www.gnu.org/licenses/>.
- *  
+ *
  */
 
 namespace OCA\Deck\Cron;
@@ -38,7 +38,7 @@ class ScheduledNoificationsTest extends \Test\TestCase {
 	/** @var ScheduledNotifications */
 	protected $scheduledNotifications;
 
-	public function setUp() {
+	public function setUp(): void {
 		parent::setUp();
 		$this->cardMapper = $this->createMock(CardMapper::class);
 		$this->notificationHelper = $this->createMock(NotificationHelper::class);
@@ -60,4 +60,4 @@ class ScheduledNoificationsTest extends \Test\TestCase {
 			->with($c1);
 		$this->scheduledNotifications->run(null);
 	}
-}
+}