Fix the warning in Structured Data Testing Tool: Missing required field "updated"

To fix the Warning: Missing required field "updated" in Structured Data Testing Tool:

• Blogger
  1. Go to Dashboard - Template
  2. Backup the template
     1. Click the "Backup/Restore" button.
     2. Click the "Download Full Template" button.
     3. Click the "Close" button.
  3. Edit the template
     1. Click the "Edit HTML" button.
     2. Check the box next to 'Expand Widget Templates'. Find the following code:
        <a class='timestamp-link' expr:href='data:post.url' rel='bookmark' title='permanent link'> <abbr class='published' expr:title='data:post.timestampISO8601' itemprop='datePublished'> <data:post.timestamp/> </abbr></a> Add "updated" to the class "'timestamp-link" and "published".
        <a class='timestamp-link updated' expr:href='data:post.url' rel='bookmark' title='permanent link'> <abbr class='published updated' expr:title='data:post.timestampISO8601' itemprop='datePublished'> <data:post.timestamp/> </abbr></a>
     3. Click the "Save" button.