Bump the rust-dependencies group with 5 updates

Bumps the rust-dependencies group with 5 updates:

| Package | From | To |
| --- | --- | --- |
| [indoc](https://github.com/dtolnay/indoc) | `2.0.5` | `2.0.6` |
| [libcnb](https://github.com/heroku/libcnb.rs) | `0.27.0` | `0.28.0` |
| [libherokubuildpack](https://github.com/heroku/libcnb.rs) | `0.27.0` | `0.28.0` |
| [winnow](https://github.com/winnow-rs/winnow) | `0.7.3` | `0.7.4` |
| [libcnb-test](https://github.com/heroku/libcnb.rs) | `0.27.0` | `0.28.0` |


Updates `indoc` from 2.0.5 to 2.0.6
- [Release notes](https://github.com/dtolnay/indoc/releases)
- [Commits](dtolnay/indoc@2.0.5...2.0.6)

Updates `libcnb` from 0.27.0 to 0.28.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.27.0...v0.28.0)

Updates `libherokubuildpack` from 0.27.0 to 0.28.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.27.0...v0.28.0)

Updates `winnow` from 0.7.3 to 0.7.4
- [Changelog](https://github.com/winnow-rs/winnow/blob/main/CHANGELOG.md)
- [Commits](winnow-rs/winnow@v0.7.3...v0.7.4)

Updates `libcnb-test` from 0.27.0 to 0.28.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.27.0...v0.28.0)

---
updated-dependencies:
- dependency-name: indoc
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
- dependency-name: libcnb
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: rust-dependencies
- dependency-name: libherokubuildpack
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: rust-dependencies
- dependency-name: winnow
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
- dependency-name: libcnb-test
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: rust-dependencies
...

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Author: dependabot[bot]