Double sales semaphore grants (#1358)

src/Universalis.DbAccess/MarketBoard/SaleStore.cs

@@ -37,7 +37,7 @@ public SaleStore(ICluster scylla, ICacheRedisMultiplexer cache, ILogger<SaleStor
         _cache = cache;
         _logger = logger;
 
-        _lock = new SemaphoreSlim(500, 500);
+        _lock = new SemaphoreSlim(1000, 1000);
 
         // Doing database initialization in a constructor is a Bad Idea and
         // can lead to timeouts killing the application, so this just gets