Merge branch 'update-lit-ssr' of github.com:e111077/astro into update…

…-lit-ssr

.changeset/gold-windows-fly.md

@@ -2,4 +2,7 @@
 '@astrojs/lit': patch
 ---
 
-Bump deps to lit-ssr 3.0 and polyfill supoprt for template[shadowrootmode] support. Also fix breakage caused by [email protected] hydration behavior requiring lit-ssr 3.0
+Update to use `@lit-labs/ssr@^3`
+**[BREAKING]** DOM shim required for Lit SSR has been greatly reduced. `window`, `document`, and other objects are no longer available in global. Most SSR-ready component code should not be affected but, if so, they can be fixed with optional chaining or by using the `isServer` environment checker from the `lit` package. See [lit.dev docs on authoring components for SSR].(https://lit.dev/docs/ssr/authoring/#browser-only-code)
+**[BREAKING]** Adds compatibility with `[email protected]` hydration behavior. Do not update if you're using `[email protected]` or lower.
+Includes support for template[shadowrootmode] support.