add changelog entry

Author: Lms24

CHANGELOG.md

@@ -13,6 +13,12 @@
   `auto.function.nestjs.cron`. If you have Sentry queries or alerts that filter on the old mechanism type, update them
   accordingly.
 
+- **fix(astro): Adjust Sentry middleware for Astro 6 ([#19745](https://github.com/getsentry/sentry-javascript/pull/19745))**
+
+  This release enableds full support for Astro v6 by adjusting our Astro SDK's middleware to some Astro-internal
+  changes. We cannot yet guarantee full support for server-islands, due to a [bug in Astro v6](https://github.com/withastro/astro/issues/15753)
+  but we'll follow up on this once the bug is fixed.
+
 ## 10.43.0
 
 ### Important Changes