Bump farming from e302b83 to b840b81 (#2412)

Bumps [farming](https://github.com/minetest-mirrors/farming) from `e302b83` to `b840b81`.
- [Commits](minetest-mirrors/farming@e302b83...b840b81)

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

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