Update CHANGES.md for v18.8.3 release
+## v18.8.3
+
+* Web UI
+ * **Improved** Kubernetes resource navigation in the sidebar
+ * **Improved** resource detail pages:
+ * **New** live request view
+ * **New** success rate graphs
+* CLI
+ * `tap` and `top` have been improved to sample up to 100 RPS
+* Control plane
+ * Injected proxy containers now have readiness and liveness probes enabled
+
+Special thanks to @sourishkrout for contributing a web readibility fix!
+
## v18.8.2
* CLI
