title: How to convert .yml to .properties with a gradle task?
body: <p>The only supported i18n formats for Spring are .properties and .xml, but it's not really optimal.
  What I'd like is to have a complex Yaml file (messages.yml and messages_xx.yml) that get converted to .properties in a Gradle task so I can queue it before Build task.</p>
  
  <p>For example, a messages.yml would look like:</p>
  
  <pre><code>group1:
    group2:
      group3:
        message1: hello
        message2: how are you?
      group4:
        message3: good
    group5:
      group6:
        message4: let's party
  </code></pre>
  
  <p>And the output .properties would be:</p>
  
  <pre><code>group1.group2.group3.message1: hello
  group1.group2.group3.message2: how are you?
  group1.group2.group4.message3: good
  group1.group5.group6.message4: let's party
  </code></pre>
  
  <p>Is there a way to achieve this?
  I didn't find existing converters.</p>