opa-react: prepare patch release (#140)

* add Features section to README
* update changeset for patch release

Author: srenatus

.changeset/smart-goats-fetch.md

@@ -0,0 +1,5 @@
+---
+"@styra/opa-react": patch
+---
+
+Tweak cache key computation and minor performance enhancements

packages/opa-react/README.md

@@ -5,6 +5,14 @@
 
 This package contains helpers for using [@styra/opa](https://www.npmjs.com/package/@styra/opa) from React.
 
+## Features
+
+* High-level, declarative components for embedding authorization decisions in your frontend code.
+* Built-in caching, deduplication, and state management based on `@tanstack/react-query`.
+* Optional **request batching** for backends that support it (Enterprise OPA, or your own implementation of the Batch API).
+
+## Details
+
 The package provides an `useAuthz` hook and a high-level `<Authz>` component.
 
 They are enabled by wrapping your App into `<AuthzProvider>`: