Bump mesecons from `da57a62` to `68171b3`

Bumps [mesecons](https://github.com/minetest-mods/mesecons) from `da57a62` to `68171b3`.
- [Release notes](https://github.com/minetest-mods/mesecons/releases)
- [Commits](https://github.com/minetest-mods/mesecons/compare/da57a6214af9b23e50e319a5902b390e613725ee...68171b3d8d08b28e850b8dd002220352e38ef7b7)

mesecons @ 68171b3d

-Subproject commit da57a6214af9b23e50e319a5902b390e613725ee
+Subproject commit 68171b3d8d08b28e850b8dd002220352e38ef7b7