updated feedad adapter documentation (#5655)

Added a description of the optional `sdkOptions` parameter

dev-docs/bidders/feedad.md

@@ -18,3 +18,4 @@ sidebarType: 1
 | `clientToken` | required | Your FeedAd client token. Check your FeedAd admin panel. | `'EiRjZDFiYzI2ZC03OTA2LTQyOTEtOGFmMC0xYzMyZmMwNTFkMDU='` | `string` |
 | `placementId` | required | A FeedAd placement ID of your choice                     | `'prebid-test'`                                          | `string` |
 | `decoration` | optional | A decoration to apply to the ad slot. See our [documentation](https://docs.feedad.com/web/feed_ad/#decorations) | `'sticky bottom height=200px'` | `string` |
+| `sdkOptions` | optional | Only required if you are using Prebid.JS in an app environment (aka hybrid App). See our [documentation](https://docs.feedad.com/web/configuration/#hybrid-app-config-parameters) | `{ hybrid_app: true, hybrid_platform: "android", bundle_id: "your.app.bundle", app_name: "Your App", limit_ad_tracking: false, advertising_id: "the user's ad id" }` | `object` |