Bump lib/nighres from ea6dd98 to e81e20e

Bumps [lib/nighres](https://github.com/nighres/nighres) from `ea6dd98` to `e81e20e`.
- [Release notes](https://github.com/nighres/nighres/releases)
- [Commits](nighres/nighres@ea6dd98...e81e20e)

---
updated-dependencies:
- dependency-name: lib/nighres
  dependency-type: direct:production
...

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