docs: fix simple typo, sqite -> sqlite

There is a small typo in README.md.

Should read `sqlite` rather than `sqite`.

README.md

@@ -166,7 +166,7 @@ $ python run_server.py
 * 添加多数据库支持
   * mysql
   * redis TODO...
-  * sqite TODO...
+  * sqlite TODO...
 * 添加抓取更多免费代理网站，目前支持的抓取的免费代理 IP 站点，目前有一些国外的站点连接不稳定
   * (国外) <http://www.freeproxylists.net/>
   * (国外) <http://gatherproxy.com/>