Bump c2pa from 0.28.3 to 0.28.4 (#109)

Bumps [c2pa](https://github.com/contentauth/c2pa-rs) from 0.28.3 to 0.28.4.
- [Release notes](https://github.com/contentauth/c2pa-rs/releases)
- [Changelog](https://github.com/contentauth/c2pa-rs/blob/main/CHANGELOG.md)
- [Commits](contentauth/c2pa-rs@v0.28.3...v0.28.4)

---
updated-dependencies:
- dependency-name: c2pa
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Cargo.toml

@@ -18,7 +18,7 @@ repository = "https://github.com/contentauth/c2pa-attacks"
 
 [dependencies]
 anyhow = "1.0"
-c2pa = { version = "0.28.3", features = ["fetch_remote_manifests", "file_io", "xmp_write"] }
+c2pa = { version = "0.28.4", features = ["fetch_remote_manifests", "file_io", "xmp_write"] }
 clap = { version = "4.4", features = ["derive"] }
 env_logger = "0.10"
 log = "0.4"