Update README.md

Signed-off-by: Yang, Bo <[email protected]>

README.md

@@ -17,7 +17,7 @@
 [![GitHub Release](https://img.shields.io/github/v/release/feast-dev/feast.svg?style=flat&sort=semver&color=blue)](https://github.com/feast-dev/feast/releases)
 
 ## Join us on Slack!
-👋👋👋 [Come say hi on Slack!](https://join.slack.com/t/feastopensource/signup)
+👋👋👋 [Come say hi on Slack!](https://communityinviter.com/apps/feastopensource/feast-the-open-source-feature-store)
 
 ## Overview
 
@@ -230,4 +230,4 @@ Thanks goes to these incredible people:
 
 <a href="https://github.com/feast-dev/feast/graphs/contributors">
   <img src="https://contrib.rocks/image?repo=feast-dev/feast" />
-</a>
+</a>