Add v3.11.0 as default Gerrit version

Change-Id: If2e57428119acd0cb9f31300b461ff56bd1c5ce5

gerrit.rb

diff --git a/gerrit.rb b/gerrit.rb
new file mode 100644
index 0000000..9262bca
--- /dev/null
+++ b/gerrit.rb
@@ -0,0 +1,4 @@
+# typed: false
+# frozen_string_literal: true
+
+class Gerrit < GerritAT3110