I did manage to get them to update just now.
The way I did it:
Keep the case and your phone VERY close together during this whole procedure, just to make sure.
1) Use AirPods with iphone and listen to music (Have WiFi and Bluetooth enabled)
2) Plug charger into airpod case, then put airpods in.
3) Place your phone right besides the charging airpods (put them super close just to make sure)
4) Open the case until the popup appears on your phone to make sure they have a connection
5) Close case and wait approx. 30 minutes (it happened immediately for me)
So contrary to common believe your phone and airpods don't have to be both charging at the same time. Just the airpods will do.