Add support for Gerrit 3.11.1

Change-Id: I965551862746330a369b66fac700d96cddde94e2
diff --git a/gerrit@3.11.1.rb b/gerrit@3.11.1.rb
new file mode 100644
index 0000000..1df7a77
--- /dev/null
+++ b/gerrit@3.11.1.rb
@@ -0,0 +1,17 @@
+# typed: false
+# frozen_string_literal: true
+
+require_relative "./gerritbase"
+
+class GerritAT3111 < GerritBase
+  def self.java_version
+    "21"
+  end
+
+  set_common_dependencies
+
+  version "3.11.1"
+  sha256 "ab4e619bd40feb95060d6efb0adafe9fde68547b3967ad4a9b2d20322084daf9"
+  url generate_url(version)
+
+end