docs(README.md): remove subplebbit.challengeTypes

README.md

@@ -379,7 +379,6 @@ PubsubSignature {
   - `subplebbit.posts`
   - `subplebbit.lastPostCid`
   - `subplebbit.pubsubTopic`
-  - `subplebbit.challengeTypes`
   - `subplebbit.rules`
   - `subplebbit.flairs`
   - `subplebbit.suggested`
@@ -1078,7 +1077,6 @@ An object which may have the following keys:
 | lastPostCid | `string` or `undefined` | The most recent post in the linked list of posts |
 | posts | `Pages` or `undefined` | Only preload page 1 sorted by 'hot', might preload more later, should include some child comments and vote counts for each post |
 | pubsubTopic | `string` or `undefined` | The string to publish to in the pubsub, a public key of the subplebbit owner's choice |
-| challengeTypes | `ChallengeType[]` or `undefined` | The challenge types provided by the subplebbit owner |
 | features | `SubplebbitFeatures` or `undefined` | The features of the subplebbit |
 | suggested | `SubplebbitSuggested` or `undefined` | The suggested client settings for the subplebbit |
 | flairs | `{[key: 'post' or 'author']: Flair[]}` or `undefined` | The list of flairs (colored labels for comments or authors) authors or mods can choose from |