build(deps): update oci-spec requirement from 0.6.6 to 0.8.1

Updates the requirements on [oci-spec](https://github.com/youki-dev/oci-spec-rs) to permit the latest version.
- [Release notes](https://github.com/youki-dev/oci-spec-rs/releases)
- [Changelog](https://github.com/youki-dev/oci-spec-rs/blob/main/release.md)
- [Commits](youki-dev/oci-spec-rs@v0.6.6...v0.8.1)

---
updated-dependencies:
- dependency-name: oci-spec
  dependency-version: 0.8.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.toml

@@ -25,7 +25,7 @@ path = "src/bin/validate.rs" # Path to the source file
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-oci-spec = { version = "0.6.6", features = ["runtime"] }
+oci-spec = { version = "0.8.1", features = ["runtime"] }
 anyhow = "1.0"
 clap = { version = "4.5.4", features = ["derive"] }
 serde_json = "1.0"