title: Email-Ext plugin templates not updated
body: <p>I'm working with jenkins pipeline. I'm using this plugin to send email notification  with the use templates. I reused an existing templates from github.</p>
  
  <p>I place the templates <code>$Jenkins_Home\email-templates\</code>.</p>
  
  <p>But my changes are not updated in the email. Still the old content was received.
  Sample code:</p>
  
  <pre><code>def call(email, subject, content, attachment = null){   
  def attachBuildLog = currentBuild.result != 'SUCCESS'
  emailext attachLog: attachBuildLog,
           body: '${SCRIPT, template="groovy-html"}',
           mimeType: 'text/html',
           subject: "${subject}",
           to: "${email}",
           replyTo: "${email}",
           recipientProviders: [[$class: 'DevelopersRecipientProvider']]
  }
  </code></pre>
  
  <p>Please advise.</p>