build(deps): update proptest-derive requirement from 0.4 to 0.5 (#29)

Updates the requirements on [proptest-derive](https://github.com/proptest-rs/proptest) to permit the latest version.
- [Release notes](https://github.com/proptest-rs/proptest/releases)
- [Changelog](https://github.com/proptest-rs/proptest/blob/master/CHANGELOG.md)
- [Commits](proptest-rs/proptest@0.4.0...proptest-derive-0.5.0)

---
updated-dependencies:
- dependency-name: proptest-derive
  dependency-type: direct:production
...

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

Author: dependabot[bot]

cdevents-sdk/Cargo.toml

@@ -13,7 +13,7 @@ description = "A Rust SDK for CDEvents"
 cloudevents-sdk = { version = "0.7", optional = true, default-features = false }
 fluent-uri = "0.1"
 proptest = { version = "1.4", optional = true }
-proptest-derive = { version = "0.4", optional = true }
+proptest-derive = { version = "0.5", optional = true }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 thiserror = "1.0"