feat: add support for Astro v7 (#92)

This change adds support for Astro v7, and updates the dev dependencies accordingly.

Recommend waiting on merging this until withastro/starlight#3991 is resolved, as the `stagger` option on CardGrid's is currently broken.  Otherwise, this appears to work great, with no additional changes.

Author: michaelfaith

packages/catppuccin-starlight/package.json

@@ -50,7 +50,7 @@
   },
   "peerDependencies": {
     "@astrojs/starlight": ">=0.38",
-    "astro": "^6.0.0"
+    "astro": "^6.0.0 || ^7.0.0"
   },
   "dependencies": {
     "@astrojs/starlight": "catalog:"