workbox-build: broadcastUpdate channelName

[mischnic]

Again broadcastUpdate with workbox-build@3.0.0-beta.1:

workbox-build wants this:

"options": {
  "broadcastUpdate": {
    "channelName": "my-update-channel"
  }
}

(resulting in new workbox.broadcastUpdate.Plugin({"channelName":"my-update-channel"}))

but it should be:

"options": {
  "broadcastUpdate": "my-update-channel"
}

(for new workbox.broadcastUpdate.Plugin("my-update-channel"), which actually works)

Without channelName, it doesn't get accepted:

Service worker generation failed: ValidationError: child "runtimeCaching" fails because ["runtimeCaching" at position 1 fails because [child "options" fails because [child "broadcastUpdate" fails because ["broadcastUpdate" must be an object]]]]

There is no {channelName: ...} in the test either:

workbox/test/workbox-broadcast-cache-update/static/sw.js

Lines 12 to 14 in 86c7ef7

	plugins: [
	new workbox.broadcastUpdate.Plugin('bcu-integration-test'),
	],

[jeffposnick]

Thanks for catching this, @mischnic!