[CHANGELOG] Prepare for v0.16.1 release (#118)

* Update changelog for v0.16.1 release

* remove unreleased line

---------

Co-authored-by: hc-github-team-secure-vault-ecosystem <hc-github-team-secure-vault-ecosystem@users.noreply.github.com>
Co-authored-by: Vinay Gopalan <vinay@hashicorp.com>

Author: hc-github-team-secure-vault-ecosystem

CHANGELOG.md

@@ -1,4 +1,9 @@
-## Unreleased
+## v0.16.1
+### March 20, 2026
+
+* Upgrade `golang.org` libs to resolve vulns (#117)
+* Automated dependency upgrades (#116)
+
 ## v0.16.0
 ### March 16, 2026