Update README to reflect public beta (#605)

* Update README.md

* Update README.md

Co-authored-by: Rich Harris <richard.a.harris@gmail.com>

README.md

@@ -1,6 +1,6 @@
 # READ THIS FIRST!
 
-We're getting ready to open up the SvelteKit public beta, which means that things will be in a stable enough state to start experimenting. Right now, even though [this repo is open](https://www.reddit.com/r/sveltejs/comments/m337r7/sveltekit_repository_is_now_public_on_github/gqmvj9k), there are still some known issues to resolve and there are aspects of the design that _will_ change over the next few days. We're close. Please bear with us!
+SvelteKit is still in beta. Expect bugs! Read more [here](https://svelte.dev/blog/sveltekit-beta), and track progress towards 1.0 [here](https://github.com/sveltejs/kit/issues?q=is%3Aopen+is%3Aissue+milestone%3A1.0).
 
 ## Documentation