build!: Bum ssi to version 0.15

Author: timothee-haudebourg

Cargo.toml

@@ -33,7 +33,7 @@ serde_json = "1.0.107"
 serde_json_path = "0.7.1"
 serde_urlencoded = "0.7.1"
 sha2 = "0.10"
-ssi = { version = "0.14", features = ["secp256r1"] }
+ssi = { version = "0.15", features = ["secp256r1"] }
 thiserror = "1.0.65"
 tokio = "1.32.0"
 tracing = "0.1.37"