deprecated AccessGrantClient delete method (#544)

Author: timea-solid

access-grant/src/main/java/com/inrupt/client/accessgrant/AccessGrantClient.java

@@ -544,7 +544,10 @@ public CompletionStage<Void> revoke(final AccessCredential credential) {
      *
      * @param credential the access credential
      * @return the next stage of completion
+     * @deprecated as of Beta4
      */
+
+    @Deprecated
     public CompletionStage<Void> delete(final AccessCredential credential) {
         final Request req = Request.newBuilder(credential.getIdentifier()).DELETE().build();
         return client.send(req, Response.BodyHandlers.discarding())