update readme

Signed-off-by: Ryan Tate <[email protected]>

README.md

@@ -167,6 +167,7 @@ yourself.
 ```rust
 use static_iref::uri;
 use serde::{Serialize, Deserialize};
+use ssi::claims::vc::syntax::NonEmptyVec;
 use ssi::prelude::*;
 
 // Defines the shape of our custom claims.
@@ -183,10 +184,10 @@ let credential = ssi::claims::vc::v1::JsonCredential::<MyCredentialSubject>::new
   Some(uri!("https://example.org/#CredentialId").to_owned()), // id
   uri!("https://example.org/#Issuer").to_owned().into(), // issuer
   DateTime::now(), // issuance date
-  vec![MyCredentialSubject {
+  NonEmptyVec::new(MyCredentialSubject {
     name: "John Smith".to_owned(),
     email: "[email protected]".to_owned()
-  }]
+  })
 );
 
 // Create a random signing key, and turn its public part into a DID URL.
@@ -216,7 +217,7 @@ let vc = cryptosuite.sign(
   ProofOptions::from_method(verification_method)
 ).await.expect("signature failed");
 ```
- 
+
 It is critical that custom claims can be interpreted as Linked-Data. In
 the above example this is done by specifying a serialization URL for each
 field of `MyCredentialSubject`. This can also be done by creating a custom