(DOCSP-24167) 1.16.4 release notes (#1008)

* (DOCSP-24167) 1.16.4 release notes

* Feedback from copy review

Author: zach-carr

source/release-notes.txt

@@ -17,6 +17,19 @@ Release Notes for |k8s-op-full|
 |k8s-op-full| 1.16 Series
 -------------------------
 
+.. _ent_op-1.16.4:
+
+|k8s-op-full| 1.16.4
+~~~~~~~~~~~~~~~~~~~~
+
+*Released 2022-08-03*
+
+MongoDB Resource
+`````````````````
+
+- Init-Ops-Manager and Operator binaries now use Go 1.18.4, which 
+  addresses security issues.
+
 .. _ent_op-1.16.3:
 
 |k8s-op-full| 1.16.3