Fix "GroupApi#getUploadFiles()" (#1196)

Author: jmini

Diff for: src/main/java/org/gitlab4j/api/GroupApi.java

@@ -2451,7 +2451,7 @@ public GroupHook addWebhook(Object groupIdOrPath, GroupHookParams groupHookParam
      * @throws GitLabApiException if any exception occurs
      */
     public List<UploadedFile> getUploadFiles(Object groupIdOrPath) throws GitLabApiException {
-        Response response = get(Response.Status.OK, null, "projects", getGroupIdOrPath(groupIdOrPath), "uploads");
+        Response response = get(Response.Status.OK, null, "groups", getGroupIdOrPath(groupIdOrPath), "uploads");
         return (response.readEntity(new GenericType<List<UploadedFile>>() {}));
     }