special_ad_categories required to create campaign in new API

[mhittle]

the special_ad_categories argument is required to create a campaign, and not included in the method to create a new campaign

[daroczig]

Hey, thanks for the report!

These functions were not really well maintained as I'm not currently using these -- sorry for that. There has been quite a lot of changes on these API endpoints, so I decided to drop the custom features and checks in R and simply pass to the API whatever the user decides, so can you please give #124 a try and report back if that works?

[aychen5]

Tried #124, I now get the error "Invalid parameter" when I add the special_ad_categories argument.

Edit: sorry, it was an issue with my spend_cap. I've resolved it.

[daroczig]

@aychen5 can you please confirm if the above PR works for your use case and I should merge that and close this ticket?