Update README.md

This PR is for adding a link to join the Discord community, which redirects users to the join.zksync.dev site. 

This update makes it easier for users to find and access all social links directly from the GitHub README. 

I thought It would be useful , So that I added,  Thanks

profile/README.md

@@ -6,6 +6,8 @@
 [![Live on Mainnet](https://img.shields.io/badge/Era%20Bridge-Live%20on%20Mainnet-blue)](https://bridge.zksync.io)
 [![Live on Mainnet](https://img.shields.io/badge/zkLite%20Checkout-Live%20on%20Mainnet-blue)](https://checkout.zksync.io)
 [![Follow us!](https://img.shields.io/twitter/follow/zksync?color=%238C8DFC&label=Follow%20%40zkSync&logo=data%3Aimage%2Fsvg%2Bxml%3Bbase64%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%2BCjwvc3ZnPgo%3D&style=flat)](https://twitter.com/zksync)
+[![Join us on Discord!](https://img.shields.io/badge/Discord-Click%20to%20Join-blue?logo=discord&style=flat)](https://join.zksync.dev/)
+
 
 ## About Matter Labs