docs: update changelog (#1114)

Author: ctrombley

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Unreleased
 
+# v1.81.0
+
 ## Enhancements
 * Adds `IngressAttributes` field to `PolicySetVersion` by @jpadrianoGo [#1092](https://github.com/hashicorp/go-tfe/pull/1092)
 * Adds `ConfirmedBy` field to `Run` by @jpadrianoGo [#1110](https://github.com/hashicorp/go-tfe/pull/1110)