Bump the libcnb group across 1 directory with 3 updates (#218)

Bumps the libcnb group with 3 updates in the / directory: [libcnb-common](https://github.com/heroku/libcnb.rs), [libcnb-data](https://github.com/heroku/libcnb.rs) and [libcnb-package](https://github.com/heroku/libcnb.rs).


Updates `libcnb-common` from 0.19.0 to 0.21.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.19.0...v0.21.0)

Updates `libcnb-data` from 0.19.0 to 0.21.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.19.0...v0.21.0)

Updates `libcnb-package` from 0.19.0 to 0.21.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.19.0...v0.21.0)

---
updated-dependencies:
- dependency-name: libcnb-common
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: libcnb
- dependency-name: libcnb-data
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: libcnb
- dependency-name: libcnb-package
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: libcnb
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.toml

@@ -36,9 +36,9 @@ clap = { version = "4", default-features = false, features = [
 ignore = "0.4"
 indexmap = "2"
 lazy_static = "1"
-libcnb-common = "=0.19.0"
-libcnb-data = "=0.19.0"
-libcnb-package = "=0.19.0"
+libcnb-common = "=0.21.0"
+libcnb-data = "=0.21.0"
+libcnb-package = "=0.21.0"
 markdown = "1.0.0-alpha.16"
 fastrand = "2"
 regex = "1"