docs: add changelog for v2.0.0

Author: uhyo

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## v2.0.0
+
+- Upgraded TypeScript to `4.5.2`.
+- Installation steps were renewed. Support for TypeScript 4.4 and prior was dropped.
+- Changed `JSON.stringify` type definitions and removed `ReadonlyJSONValue` type. (https://github.com/uhyo/better-typescript-lib/issues/5)
+
 ## v1.2.0
 
 - Upgraded TypeScript to `4.4.3`.