GitHubGroupBackend: Accept CurrentUser instead of IdentifiedUser

In Idc9a7630e8d the signature of GroupBackend#membershipsOf was changed
to accept more general CurrentUser instead of IdentifiedUser.

Change-Id: I8a3c6c5160dc4b654e8b3a094a6a3fbd12dfb503

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/group/GitHubGroupBackend.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/group/GitHubGroupBackend.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/group/GitHubGroupBackend.java
index 21d6732..5f74078 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/group/GitHubGroupBackend.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/group/GitHubGroupBackend.java
@@ -25,7 +25,7 @@
 import com.google.gerrit.entities.AccountGroup.UUID;
 import com.google.gerrit.entities.GroupDescription.Basic;
 import com.google.gerrit.entities.GroupReference;
-import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupMembership;
 import com.google.gerrit.server.project.ProjectState;
@@ -111,7 +111,7 @@
   }
 
   @Override
-  public GroupMembership membershipsOf(IdentifiedUser user) {
+  public GroupMembership membershipsOf(CurrentUser user) {
     String username = user.getUserName().orElse(null);
     if (Strings.isNullOrEmpty(username)) {
       return GroupMembership.EMPTY;