Bump serverless-layers from 2.5.1 to 2.8.5

Bumps [serverless-layers](https://github.com/agutoli/serverless-layers) from 2.5.1 to 2.8.5.
- [Changelog](https://github.com/agutoli/serverless-layers/blob/master/CHANGELOG.md)
- [Commits](https://github.com/agutoli/serverless-layers/commits/2.8.5)

---
updated-dependencies:
- dependency-name: serverless-layers
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>