[chore] add changeset for create-svelte (#3430)

missed in #3384
closes #3417

Author: dummdidumm

Diff for: .changeset/real-icons-study.md

@@ -0,0 +1,5 @@
+---
+'create-svelte': patch
+---
+
+Breaking: change app.render signature to (request: Request) => Promise (#3384)