Add maintenance announcement tag helper

Change-Id: Ie4a18bf28e38613f9f2faded9c84be023f517b34
diff --git a/Makefile.PL b/Makefile.PL
index 3c72084..6039ff2 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -29,6 +29,7 @@
     'Mojolicious::Plugin::AutoSecrets' => 0.006,
     'Mojolicious::Plugin::TagHelpers::ContentBlock' => 0.11,
     'Cache::FastMmap' => 1.57,
+    'DateTime' => 1.63,
 
     # Required for Mojolicious::Plugin::CHI
     'Data::Serializer' => 0.65,