Require modern List::Util dependency for older perl bundles

Change-Id: If7b0505e0b9e9dbe70f6381de683030fe98d2b4d
diff --git a/Makefile.PL b/Makefile.PL
index 32d88fd..56f1696 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -32,6 +32,9 @@
     # Required for Data::Serializer at the moment
     'JSON' => 4.03,
 
+    # Required for older perl bundles
+    'List::Util' => 1.45,
+
     # Required for bundled plugins
     'Mojolicious::Plugin::Piwik' => 0.28,