Updated README.md (#307)

I suggest this minor change since the old link for the Data Engineer Things Community, doesn't work. So I looked for the right link and replaced it.

Author: Abdelhaq-Bensghir

README.md

@@ -34,7 +34,7 @@ Top 3 must read books are:
 Top must-join communities for DE:
 - [DataExpert.io Community Discord](https://discord.gg/JGumAXncAK)
 - [Data Talks Club Slack](https://datatalks.club/slack)
-- [Data Engineer Things Community](https://www.dataengineerthings.org/aboutus/)
+- [Data Engineer Things Community](https://dataengineerthings.slack.com/join/shared_invite/zt-34mqkmrxs-59yWxQRruwq5_h~7PKRFuQ#/shared-invite/email)
 
 Top must-join communities for ML:
 - [AdalFlow Discord](https://discord.com/invite/ezzszrRZvT)