docs: Update slack invite link

Author: farioas

README.md

@@ -1,7 +1,7 @@
 # Label Studio Frontend · ![GitHub](https://img.shields.io/github/license/heartexlabs/label-studio?logo=heartex) ![build](https://github.com/heartexlabs/label-studio-frontend/workflows/Build%20and%20Test/badge.svg) ![npm audit](https://github.com/heartexlabs/label-studio-frontend/actions/workflows/npm_audit.yml/badge.svg)
  ![GitHub release](https://img.shields.io/github/v/release/heartexlabs/label-studio-frontend?include_prereleases) · :sunny:
 
-[Website](https://labelstud.io/) • [Docs](https://labelstud.io/guide) • [Twitter](https://twitter.com/heartexlabs) • [Join Slack Community <img src="https://go.heartex.net/docs/images/slack-mini.png" width="18px"/>](https://docs.google.com/forms/d/e/1FAIpQLSdLHZx5EeT1J350JPwnY2xLanfmvplJi6VZk65C2R4XSsRBHg/viewform?usp=sf_link)
+[Website](https://labelstud.io/) • [Docs](https://labelstud.io/guide) • [Twitter](https://twitter.com/heartexlabs) • [Join Slack Community <img src="https://go.heartex.net/docs/images/slack-mini.png" width="18px"/>](https://slack.labelstudio.heartex.com)
 
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