Preparing for v3.21.3 release.

Author: halx99

README.md

@@ -1,6 +1,6 @@
 # yasio - *Y*et *A*nother *S*ocket *IO* service
 [![Build Status](https://travis-ci.org/halx99/yasio.svg?branch=master)](https://travis-ci.org/halx99/yasio)
-[![Release](https://img.shields.io/badge/release-v3.21.2-blue.svg)](https://github.com/halx99/yasio/releases)
+[![Release](https://img.shields.io/badge/release-v3.21.3-blue.svg)](https://github.com/halx99/yasio/releases)
 [![996.icu](https://img.shields.io/badge/link-996.icu-red.svg)](https://996.icu)
 [![LICENSE](https://img.shields.io/badge/license-Anti%20996-blue.svg)](https://github.com/halx99/yasio/blob/master/LICENSE)
 [![GitHub stars](https://img.shields.io/github/stars/halx99/yasio.svg?label=Stars)](https://github.com/halx99/yasio)