Blue Billywig bid adapter - add video param to docs (#2198)

* add Blue Billywig bidder adaptor dev docs

* Add missing empty line

* move empty line to right place...

Co-authored-by: Klaas-Jan Boon <klaas-janboon@live.nl>
Co-authored-by: Klaas-Jan Boon <klaas-janboon@ip-172-16-224-85.eu-west-1.compute.internal>

dev-docs/bidders/bluebillywig.md

@@ -22,3 +22,4 @@ userIds: britepoolId, criteo, id5Id, identityLink, liveIntentId, netId, parrable
 | `accountId` | required | Your publication ID at Blue Billywig | `642` | `integer` |
 | `rendererCode` | required | The name of the renderer to use in your Blue Billywig publication | `"renderer"` | `string` |
 | `connections` | required | Back-ends to connect with. For every value in this a param matching the back-end should exist too. | `["bluebillywig"]` | `array` |
+| `video` | optional | Any OpenRTB 2.5 video params to additionally send along to the SSPs. | `{"maxduration": 30}` | `object` |