meta-*: bump layers/sw/meta-rauc from 76b9779 to a0f4a8b

Bumps [layers/sw/meta-rauc](https://github.com/rauc/meta-rauc) from `76b9779` to `a0f4a8b`.
- [Commits](rauc/meta-rauc@76b9779...a0f4a8b)

---
updated-dependencies:
- dependency-name: layers/sw/meta-rauc
  dependency-version: a0f4a8b9986954239850b9d4256c003c91e6b931
  dependency-type: direct:production
...

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Author: dependabot[bot]