Mention migration guide

Author: Bromeon

website/content/dev/2025-05-31-may-2025-update.md

@@ -150,7 +150,9 @@ Lots of smaller refactorings have happened to keep the development process as sm
 We hope you enjoy the improvements since the [2024 review][dev-update-2024], and wish you great success in your projects! 
 Whether those are games, plugins or other software, join our [Discord][discord] and let us know how you use the library in `#showcase`!
 
-As always, the complete list of changes is available in the [changelog][changelog]. See also recently merged [pull requests][pull-requests].
+As always, the complete list of changes is available in the [changelog][changelog]. 
+See also our [v0.2 -> v0.3 migration guide][book-migrate] and recently merged [pull requests][pull-requests].
+
 
 
 [#650]: https://github.com/godot-rust/gdext/pull/650
@@ -165,6 +167,7 @@ As always, the complete list of changes is available in the [changelog][changelo
 [discord]: https://discord.gg/aKUCJ8rJsc
 [issues]: https://github.com/godot-rust/gdext/issues
 [pull-requests]: https://github.com/godot-rust/gdext/pulls?q=is%3Apr+is%3Amerged
+[book-migrate]: https://godot-rust.github.io/book/migrate/v0.3.html
 
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