Added webcomponents mention & the 3.30.1 release

site/content/blog/2020-12-01-whats-new-in-svelte-december-2020.md

@@ -9,8 +9,8 @@ It's the last "What's new in Svelte" of the year and there's lots to celebrate!
 
 ## New features & impactful bug fixes
 
-1. `slot` components now support spread props: `<slot {...foo} />` (**3.30.0**)
-2. A new `hasContext` lifecycle function makes it easy to check whether a `key` has been set in the context of a parent component (**3.30.0**, [Docs](https://svelte.dev/docs#hasContext))
+1. `$$props`, `$$restProps`, and `$$slots` are all now supported in custom web components (**3.29.5**, [Example](https://svelte.dev/repl/ad8e6f39cd20403dacd1be84d71e498d?version=3.29.5)) and  `slot` components now support spread props: `<slot {...foo} />` (**3.30.0**)
+2. A new `hasContext` lifecycle function makes it easy to check whether a `key` has been set in the context of a parent component (**3.30.0** & **3.30.1**, [Docs](https://svelte.dev/docs#hasContext))
 3. `SvelteComponent` is now typed which makes it easier to add typed classes that extend base Svelte Components. Component library and framework authors rejoice! An example: `export class YourComponent extends SvelteComponent<{aProp: boolean}, {click: MouseEvent}, {default: {aSlot: string}}> {}` (**3.30.0**, [RFC](https://github.com/sveltejs/rfcs/pull/37))
 4. Transitions within `{:else}` blocks should now complete successfully (**3.29.5**, [Example](https://svelte.dev/repl/49cef205e5da459594ef2eafcbd41593?version=3.29.5))
 5. Svelte now includes an export map, which explicitly states which files can be imported from its npm package. This should significantly improve debugging in web dev tools (**3.29.5** with some fixes in **3.29.6**, **3.29.7** and **3.30.0**)