Update RC blog post to use rc2

Author: gaearon

content/blog/2020-08-10-react-v17-rc.md

@@ -272,20 +272,20 @@ We encourage you to try React 17.0 Release Candidate soon and [raise any issues]
 To install React 17 RC with npm, run:
 
 ```bash
-npm install react@17.0.0-rc.1 react-dom@17.0.0-rc.1
+npm install react@17.0.0-rc.2 react-dom@17.0.0-rc.2
 ```
 
 To install React 17 RC with Yarn, run:
 
 ```bash
-yarn add react@17.0.0-rc.1 react-dom@17.0.0-rc.1
+yarn add react@17.0.0-rc.2 react-dom@17.0.0-rc.2
 ```
 
 We also provide UMD builds of React via a CDN:
 
 ```html
-<script crossorigin src="https://unpkg.com/react@17.0.0-rc.1/umd/react.production.min.js"></script>
-<script crossorigin src="https://unpkg.com/react-dom@17.0.0-rc.1/umd/react-dom.production.min.js"></script>
+<script crossorigin src="https://unpkg.com/react@17.0.0-rc.2/umd/react.production.min.js"></script>
+<script crossorigin src="https://unpkg.com/react-dom@17.0.0-rc.2/umd/react-dom.production.min.js"></script>
 ```
 
 Refer to the documentation for [detailed installation instructions](/docs/installation.html).