chore: update readme todo [ci skip]

Author: yyx990803

README.md

@@ -6,12 +6,8 @@ The current codebase has basic feature parity with v2.x, together with the chang
 
 Please note that there could still be undocumented behavior inconsistencies with 2.x. When you run into such a case, please make sure to first check if the behavior difference has already been proposed in an existing RFC. If the inconsistency is not part of an RFC, then it's likely unintended, and an issue should be opened (please make sure to use the [issue helper](https://new-issue.vuejs.org/?repo=vuejs/vue-next) when opening new issues).
 
-## TODOs as of 3.0.0-alpha.5
+## TODOs as of 3.0.0-alpha.9
 
-- Suspense support in SSR
-- SSR Hydration mismatch handling
-- SSR vnode directive support
-- SSR integration tests
 - 2.x compatible async component support
 
 ## Known Issues