write_rockspec: Add support for Lua 5.4
write_rockspec: Add support for Lua 5.4

tarantool/luarocks,keplerproject/luarocks,tarantool/luarocks,tarantool/luarocks,keplerproject/luarocks,keplerproject/luarocks,luarocks/luarocks,keplerproject/luarocks,luarocks/luarocks,luarocks/luarocks