fix(deps): update dependency astro to v4

Author: renovate[bot]

packages/documentation/package.json

@@ -11,7 +11,7 @@
   "dependencies": {
     "@astrojs/starlight": "^0.13.1",
     "@interledger/docs-design-system": "^0.2.1",
-    "astro": "3.6.4",
+    "astro": "4.2.1",
     "astro-graphql-plugin": "^0.1.0",
     "graphql": "^16.8.1",
     "mermaid": "^10.6.1",