Explicitly explain EOL about td-agent

Signed-off-by: Kentaro Hayashi <[email protected]>

views/download_fluent_package.erb

@@ -176,6 +176,18 @@
       <br/>
 
       <h4><a name=td-agent></a>Treasure Agent (td-agent)</h4>
+      <div class="alert alert-danger">
+        <p>
+          Treasure Agent (td-agent) had already reached <a href="https://www.fluentd.org/blog/schedule-for-td-agent-4-eol">End of Life (EOL)</a> in Dec, 2023.
+        </p>
+        <p>
+          There is no support anymore - Thus No new release and No security update.
+        </p>
+        <p>
+          td-agent user should migrate to Fluent Package. It was designed to support migration from td-agent and it provides Long Term Support (LTS) version.
+          See <a href="https://www.fluentd.org/blog/upgrade-td-agent-v4-to-v5">Upgrade to fluent-package v5</a> for migration.
+        </p>
+      </div>
       <table class="table table-bordered">
         <thead>
           <tr>