refactor: drop readonly in client classes (#305)

Author: simPod

src/Client/PsrClickHouseAsyncClient.php

@@ -21,7 +21,7 @@
 
 use function uniqid;
 
-readonly class PsrClickHouseAsyncClient implements ClickHouseAsyncClient
+class PsrClickHouseAsyncClient implements ClickHouseAsyncClient
 {
     private SqlFactory $sqlFactory;
 

src/Client/PsrClickHouseClient.php

@@ -36,7 +36,7 @@
 use function sprintf;
 use function uniqid;
 
-readonly class PsrClickHouseClient implements ClickHouseClient
+class PsrClickHouseClient implements ClickHouseClient
 {
     private ValueFormatter $valueFormatter;