add opcache to list of php packages

opcache is used later, but was never added to phpExt.

nixos/modules/services/web-apps/moodle.nix

@@ -57,7 +57,7 @@ let
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
 
   phpExt = pkgs.php74.withExtensions
-        ({ enabled, all }: with all; [ iconv mbstring curl openssl tokenizer xmlrpc soap ctype zip gd simplexml dom  intl json sqlite3 pgsql pdo_sqlite pdo_pgsql pdo_odbc pdo_mysql pdo mysqli session zlib xmlreader fileinfo filter ]);
+        ({ enabled, all }: with all; [ iconv mbstring curl openssl tokenizer xmlrpc soap ctype zip gd simplexml dom  intl json sqlite3 pgsql pdo_sqlite pdo_pgsql pdo_odbc pdo_mysql pdo mysqli session zlib xmlreader fileinfo filter opcache ]);
 in
 {
   # interface