Update CHANGELOG for 8.1.0

(cherry picked from commit 5dc8889)

Author: chriskrycho

CHANGELOG.md

@@ -1,4 +1,13 @@
 
+## v8.1.0 (2022-12-20)
+Back-ports built-in TypeScript support from 9.0.0 (see below) to decouple that from the Ember 4.x upgrade.
+
+#### :rocket: Enhancement
+* [#839](https://github.com/ember-cli/ember-resolver/pull/839) Backport types to 8.x ([@chriskrycho](https://github.com/chriskrycho))
+
+#### Committers: 1
+- Chris Krycho ([@chriskrycho](https://github.com/chriskrycho))
+
 ## v9.0.0 (2022-12-19)
 TL;DR: drop some old versions, and ship TypeScript type definitions.