FilteredRepository: Stop using deprecated RefDatabase#getRefs

Change-Id: I93b40f1688c3aea4ab08873bbf2756a6c8d80bc0
diff --git a/src/main/java/com/googlesource/gerrit/plugins/gitiles/FilteredRepository.java b/src/main/java/com/googlesource/gerrit/plugins/gitiles/FilteredRepository.java
index 3dee013..c3bed8a 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/gitiles/FilteredRepository.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/gitiles/FilteredRepository.java
@@ -232,7 +232,7 @@
       try {
         refs =
             perm.filter(
-                git.getRefDatabase().getRefs(prefix),
+                git.getRefDatabase().getRefsByPrefix(prefix),
                 git,
                 RefFilterOptions.builder().setFilterTagsSeparately(true).build());
       } catch (PermissionBackendException e) {