Bump mods/screwdriver from 55f6504 to 9439c1d

Bumps [mods/screwdriver](https://github.com/minetest-game/screwdriver) from `55f6504` to `9439c1d`.
- [Commits](minetest-game/screwdriver@55f6504...9439c1d)

---
updated-dependencies:
- dependency-name: mods/screwdriver
  dependency-type: direct:production
...

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