release: add changelog for v0.18.0

Author: Totodore

crates/socketioxide/CHANGELOG.md

@@ -1,4 +1,7 @@
 # socketioxide 0.18.0
+* feat(**breaking**): remove sync handlers to gain 50% of compilation speed.
+* feat: Socket rooms will be removed only **after** the disconnect handler execution,
+making them available in the disconnect handler (thanks @Mettwasser).
 
 # socketioxide 0.17.2
 * fix: issue [#527](https://github.com/Totodore/socketioxide/issues/527). Socketioxide failed to build with the `tracing` flag enable and with `tracing-attributes` set to `v0.1.28`.