title: Match multiple field names in logstash mutate filter
body: <p>I would like to convert all metrics* fields into floats for logstash. For a structure like</p>
  
  <pre><code>{
    "metric1":"1",
    "metric2":"2"
  }
  </code></pre>
  
  <p>I'd like to do something like</p>
  
  <pre><code>mutate {
     convert =&gt; {"metric*" =&gt; "float" }
  }
  </code></pre>
  
  <p>Is that possible?</p>