title: Workbox not Overriding Default Strategy
body: <p>Having some issues overriding the default cacheFirst strategy in Nuxt Workbox.</p>
  
  <p>Expected behavior: cacheFirst is replaced by staleWhileRevalidate</p>
  
  <p>nuxt.config.js:</p>
  
  <pre><code>workbox: {
    runtimeCaching: [
      {
        urlPattern: '/_nuxt/.*',
        handler: 'staleWhileRevalidate',
        method: 'GET'
      }
    ]
  }
  </code></pre>
  
  <p>Current behavior: Creates a new entry instead of overriding.</p>
  
  <p>sw.js:</p>
  
  <pre><code>workbox.routing.registerRoute(new RegExp('/_nuxt/.*'),
  workbox.strategies.cacheFirst({}), 'GET')
  
  workbox.routing.registerRoute(new RegExp('/.*'), 
  workbox.strategies.networkFirst({}), 'GET')
  
  workbox.routing.registerRoute(new RegExp('/_nuxt/.*'), 
  workbox.strategies.staleWhileRevalidate({}), 'GET')
  </code></pre>
  
  <p>Not sure what I am missing. Thank  you for the help. Cheers!</p>