fix: use correct room versions

src/client_server/capabilities.rs

@@ -17,7 +17,6 @@ use rocket::get;
 #[tracing::instrument]
 pub async fn get_capabilities_route() -> ConduitResult<get_capabilities::Response> {
     let mut available = BTreeMap::new();
-    available.insert(RoomVersionId::Version5, RoomVersionStability::Stable);
     available.insert(RoomVersionId::Version6, RoomVersionStability::Stable);
 
     let mut capabilities = Capabilities::new();