some test updates

trifid-pki/src/test.rs

@@ -34,7 +34,7 @@ fn certificate_serialization() {
             is_ca: false,
             issuer: "1234567890abcedfghij1234567890ab".to_string(),
         },
-        signature: hex::decode("1234567890abcedfghij1234567890ab").unwrap(),
+        signature: b"1234567890abcedfghij1234567890ab".to_vec(),
     };
 
     let bytes = cert.serialize().unwrap();