CacheableResponsePlugin does ignore a specified header while routing a request

**Library Affected**:
_workbox-sw_

**Browser & Platform**:
_Could only check Google Chrome_

**Issue Description**:
I am using the CacheableResponsePlugin in a service worker definition to route cacheable and non-cacheable documents with two different caching strategies. If the header "pwa-cache-control: no-cache" is set in the response I'd like to apply the NetworkOnly strategy and in case the header is missing CacheFirst.

What actually happens though, all documents are handled by the NetworkOnly route, no matter if the pwa-cache-control header is present or missing. I could verify that in the debug view. Do I miss something here or is the header feature of the plugin broken?

If I remove the first route, the CacheFirst strategy is used as expected for all documents.

Btw, with this approach I am assuming that routes are considered in the order of being registered, correct?

Here is the respective section within my sw.js

```
// don't cache pages with no-cache header
registerRoute(
({request}) => request.destination === 'document',
new NetworkOnly({
plugins: [
new CacheableResponsePlugin({
headers: {
'pwa-cache-control': 'no-cache',
},
}),
],
})
);

// but cache other pages
registerRoute(
({request}) => request.destination === 'document',
new CacheFirst({
cacheName: 'html-cache',
plugins: [
new ExpirationPlugin({
maxAgeSeconds: 7 * 24 * 60 * 60,
}),
],
})
);
```