fix: leading 0 before seconds

lib/podcast_feed_web/views/feed_view.ex

@@ -3,7 +3,7 @@ defmodule PodcastFeedWeb.FeedView do
 
   def format_length(length) do
     min = length / 60 |> trunc()
-    sec = length - (min * 60)
+    sec = length - (min * 60) |> Integer.to_string |> String.pad_leading(2, "0")
     "#{min}:#{sec}"
   end
 end