Update README.md

Author: shahar4

README.md

@@ -27,4 +27,4 @@ See [LICENSE-MIT](LICENSE-MIT) for details.
 - [GitHub](https://github.com/matter-labs)
 - [Twitter](https://twitter.com/zksync)
 - [Twitter for Devs](https://twitter.com/zkSyncDevs)
-- [Discord](https://discord.gg/px2ar7w)
+- [Discord](https://join.zksync.dev)