Compile warning possible buffer overflow

[mdblack98]

/home/mdblack98/src/freedv-gui/build_linux/sioclient_src/lib/asio/asio/include/asio/detail/impl/socket_ops.ipp:2109:29: warning: ‘%lu’ directive writing between 1 and 20 bytes into a region of size 16 [-Wformat-overflow=]
2109 | sprintf(if_name + 1, "%lu", scope_id);