Add changeset entry

Author: simolus3

.changeset/short-gifts-turn.md

@@ -0,0 +1,8 @@
+---
+'@powersync/op-sqlite': patch
+'@powersync/react-native': patch
+'@powersync/node': patch
+'@powersync/web': patch
+---
+
+Update PowerSync core extension to 0.4.0