return utc from clock

app/Auth/Clock.php

@@ -6,5 +6,8 @@ use DateTimeImmutable;
 
 interface Clock
 {
+    /**
+     * Returns the current time in UTC.
+     */
     public function now(): DateTimeImmutable;
 }

app/Auth/SystemClock.php

@@ -3,11 +3,12 @@
 namespace App\Auth;
 
 use DateTimeImmutable;
+use DateTimeZone;
 
 class SystemClock implements Clock
 {
     public function now(): DateTimeImmutable
     {
-        return new DateTimeImmutable();
+        return new DateTimeImmutable('now', new DateTimeZone('UTC'));
     }
 }