Correct maxAllowedPacket default value mentioned in docs to match the new setting (#1412)

Author: sjmudd

README.md

@@ -285,7 +285,7 @@ Type:          decimal number
 Default:       64*1024*1024
 ```
 
-Max packet size allowed in bytes. The default value is 4 MiB and should be adjusted to match the server settings. `maxAllowedPacket=0` can be used to automatically fetch the `max_allowed_packet` variable from server *on every connection*.
+Max packet size allowed in bytes. The default value is 64 MiB and should be adjusted to match the server settings. `maxAllowedPacket=0` can be used to automatically fetch the `max_allowed_packet` variable from server *on every connection*.
 
 ##### `multiStatements`