Add vc-refresh-service context to example.

Author: msporny

index.html

@@ -3399,7 +3399,8 @@ <h3>Refreshing</h3>
 {
   "@context": [
     "https://www.w3.org/ns/credentials/v2",
-    "https://www.w3.org/ns/credentials/examples/v2"
+    "https://www.w3.org/ns/credentials/examples/v2",
+    "https://w3id.org/vc-refresh-service/v1"
   ],
   "id": "http://university.example/credentials/3732",
   "type": ["VerifiableCredential", "ExampleDegreeCredential"],
@@ -3414,7 +3415,7 @@ <h3>Refreshing</h3>
   },
   <span class="highlight">"refreshService": {
     "type": "VerifiableCredentialRefreshService2021",
-    "url": "https://university.example/flows/refresh-degree",
+    "url": "https://university.example/workflows/refresh-degree",
     "validFrom": "2021-09-01T19:23:24Z",
     "validUntil": "2022-02-01T19:23:24Z"
   }</span>
@@ -3424,7 +3425,7 @@ <h3>Refreshing</h3>
         <p>
 In the example above, the [=issuer=] specifies an automatic
 `refreshService` that can be used by directing the [=holder=] to
-`https://university.example/flows/refresh-degree`.
+`https://university.example/workflows/refresh-degree`.
         </p>
 
       </section>