Update contribution guidelines to include Slack community details

Author: xxubai

amoro-site/content/community/how-to-contribute.md

@@ -15,7 +15,12 @@ If you have any questions, suggestions, or improvement ideas when using Amoro, y
 
 * [Issue Tracker](https://github.com/apache/amoro/issues) - for tracking bugs, ideas, plans, etc.
 * [GitHub Discussions](https://github.com/apache/amoro/discussions) - second to the mailing list for anything else you want to share or ask.
-* WeChat Group - add `kllnn999` as a friend on WeChat and specify `Amoro lover`. You will be invited to join the Amoro WeChat group.
+* WeChat Group - add `kllnn999` as a friend and request to join the group.
+* Slack - You can join the Amoro community on Slack. Amoro channel is in ASF Slack workspace.
+  - Anyone with an @apache.org email address can become a full member of the ASF Slack workspace.
+  - Search [Amoro channel](https://the-asf.slack.com/archives/C06RZ9UHUTH) and join it.
+  - If you don't have an @apache.org email address, you can email to `dev@amoro.apache.org` to apply for an
+    [ASF Slack invitation](https://infra.apache.org/slack.html). Then join [Amoro channel](https://the-asf.slack.com/archives/C06RZ9UHUTH).
 
 ## Contributing Guide