Update CHANGES.md for v18.7.3 release
+## v18.7.3
+
+Linkerd2 v18.7.3 completes the rebranding from Conduit to Linkerd2, and improves
+overall performance and stability.
+
+* Proxy
+ * **Improved** CPU utilization by ~20%
+* Web UI
+ * **Experimental** `/tap` page now supports additional filters
+* Control Plane
+ * Updated all k8s.io dependencies to 1.11.1
+
## v18.7.2
Linkerd2 v18.7.2 introduces new stability features as we work toward production
