Bump mobs_monster from 1a576f2 to 6de7ee6 (#2375)

Bumps [mobs_monster](https://github.com/minetest-mirrors/mobs_monster) from `1a576f2` to `6de7ee6`.
- [Commits](minetest-mirrors/mobs_monster@1a576f2...6de7ee6)

---
updated-dependencies:
- dependency-name: mobs_monster
  dependency-type: direct:production
...

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