user/all-features-by-client.md: group calls on ios

https://jami.net/dev-update-14/
It's finally here: Group calls on iOS!

https://review.jami.net/c/jami-client-ios/+/30822

GitLab: #219

Change-Id: I55fff8e849245acef6caf27f47148749d576da08

user/all-features-by-client.md

@@ -194,7 +194,7 @@
   - 🧪
   - ✓
   - 🧪
-  - ×
+  - ✓
   - ×
 * - Host call conference
   - ✓