Update contact information (#123)

README.md

@@ -199,8 +199,10 @@ You can set those environment variables by `--set oap.env.<ENV_NAME>=<ENV_VALUE>
 # Contact Us
 * Submit an [issue](https://github.com/apache/skywalking/issues)
 * Mail list: **[email protected]**. Mail to `[email protected]`, follow the reply to subscribe the mail list.
-* Join `skywalking` channel at [Apache Slack](https://join.slack.com/t/the-asf/shared_invite/enQtNzc2ODE3MjI1MDk1LTAyZGJmNTg1NWZhNmVmOWZjMjA2MGUyOGY4MjE5ZGUwOTQxY2Q3MDBmNTM5YTllNGU4M2QyMzQ4M2U4ZjQ5YmY). If the link is not working, find the latest one at [Apache INFRA WIKI](https://cwiki.apache.org/confluence/display/INFRA/Slack+Guest+Invites).
-* QQ Group: 392443393(2000/2000, not available), 901167865(available)
+* Send `Request to join SkyWalking slack` mail to the mail list(`[email protected]`), we will invite you in.
+* For Chinese speaker, send `[CN] Request to join SkyWalking slack` mail to the mail list(`[email protected]`), we will invite you in.
+* Twitter, [ASFSkyWalking](https://twitter.com/AsfSkyWalking)
+* [bilibili B站 视频](https://space.bilibili.com/390683219)
 
 # LICENSE
 Apache 2.0