fix slack URL

Author: mlsmaycon

src/pages/how-to/manage-posture-checks.mdx

@@ -134,5 +134,5 @@ Following these steps, you can effectively implement and manage NetBird's Postur
 
 - Make sure to [star us on GitHub](https://github.com/netbirdio/netbird)
 - Follow us [on Twitter](https://twitter.com/netbird)
-- Join our [Slack Channel](https://join.slack.com/t/netbirdio/shared_invite/zt-2p5zwhm4g-8fHollzrQa5y4PZF5AEpvQ)
+- Join our [Slack Channel](https://join.slack.com/t/netbirdio/shared_invite/zt-2utg2ncdz-W7LEB6toRBLE1Jca37dYpg)
 - NetBird [latest release](https://github.com/netbirdio/netbird/releases) on GitHub