Update oci-spec requirement from 0.6 to 0.7

Updates the requirements on [oci-spec](https://github.com/containers/oci-spec-rs) to permit the latest version.
- [Release notes](https://github.com/containers/oci-spec-rs/releases)
- [Changelog](https://github.com/containers/oci-spec-rs/blob/main/release.md)
- [Commits](youki-dev/oci-spec-rs@v0.6.0...v0.6.8)

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

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

Cargo.toml

@@ -33,7 +33,7 @@ futures = "0.3.19"
 libc = "0.2.112"
 log = {version = "0.4.2", features=["kv_unstable"]}
 nix = "0.29"
-oci-spec = "0.6"
+oci-spec = "0.7"
 os_pipe = "1.1"
 prctl = "1.0.0"
 prost = "0.13"