Update ring requirement from ^0.16.2 to ^0.17.5

Updates the requirements on [ring](https://github.com/briansmith/ring) to permit the latest version.
- [Commits](https://github.com/briansmith/ring/commits)

---
updated-dependencies:
- dependency-name: ring
  dependency-type: direct:production
...

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

Cargo.toml

@@ -51,7 +51,7 @@ pqcrypto-kyber = { version = "0.7", optional = true }
 pqcrypto-traits = { version = "0.3", optional = true }
 
 # ring crypto provider
-ring = { version = "^0.16.2", optional = true, features = ["std"] }
+ring = { version = "^0.17.5", optional = true, features = ["std"] }
 # libsodium crypto provider
 sodiumoxide = { version = "0.2", optional = true }
 byteorder = { version = "1.4", optional = true }