Bump the libcnb group with 3 updates

Bumps the libcnb group with 3 updates: [libcnb](https://github.com/heroku/libcnb.rs), [libherokubuildpack](https://github.com/heroku/libcnb.rs) and [libcnb-test](https://github.com/heroku/libcnb.rs).


Updates `libcnb` from 0.17.0 to 0.19.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.17.0...v0.19.0)

Updates `libherokubuildpack` from 0.17.0 to 0.19.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.17.0...v0.19.0)

Updates `libcnb-test` from 0.17.0 to 0.19.0
- [Release notes](https://github.com/heroku/libcnb.rs/releases)
- [Changelog](https://github.com/heroku/libcnb.rs/blob/main/CHANGELOG.md)
- [Commits](heroku/libcnb.rs@v0.17.0...v0.19.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.lock

@@ -16,8 +16,8 @@ glob = "0.3"
 indoc = "2"
 # libcnb has a much bigger impact on buildpack behaviour than any other dependencies,
 # so it's pinned to an exact version to isolate it from lockfile refreshes.
-libcnb = "=0.17.0"
-libherokubuildpack = { version = "=0.17.0", default-features = false, features = ["digest"] }
+libcnb = "=0.19.0"
+libherokubuildpack = { version = "=0.19.0", default-features = false, features = ["digest"] }
 rand = "0.8"
 # TODO: Consolidate on either the regex crate or the fancy-regex crate, since this repo currently uses both.
 regex = "1"
@@ -29,5 +29,5 @@ ureq = { version = "2", default-features = false, features = ["tls"] }
 url = "2"
 
 [dev-dependencies]
-libcnb-test = "=0.17.0"
+libcnb-test = "=0.19.0"
 toml = "0.8"

buildpacks/ruby/Cargo.toml

@@ -24,8 +24,8 @@ indoc = "2"
 lazy_static = "1"
 # libcnb has a much bigger impact on buildpack behaviour than any other dependencies,
 # so it's pinned to an exact version to isolate it from lockfile refreshes.
-libcnb = "=0.17.0"
-libherokubuildpack = { version = "=0.17.0", default-features = false, features = ["command"] }
+libcnb = "=0.19.0"
+libherokubuildpack = { version = "=0.19.0", default-features = false, features = ["command"] }
 regex = "1"
 serde = "1"
 sha2 = "0.10"
@@ -36,6 +36,6 @@ walkdir = "2"
 [dev-dependencies]
 filetime = "0.2"
 indoc = "2"
-libcnb-test = "=0.17.0"
+libcnb-test = "=0.19.0"
 pretty_assertions = "1"
 toml = "0.8"