Bump privdrop from 0.5.6 to 0.5.7

Bumps [privdrop](https://github.com/jedisct1/rust-privdrop) from 0.5.6 to 0.5.7.
- [Commits](jedisct1/rust-privdrop@0.5.6...0.5.7)

---
updated-dependencies:
- dependency-name: privdrop
  dependency-version: 0.5.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]