Update Discord URL

Author: timofurrer

README.md

@@ -12,5 +12,5 @@ We welcome you to contribute [on GitLab](https://gitlab.com/gitlab-org/terraform
 - [Project on GitLab](https://gitlab.com/gitlab-org/terraform-provider-gitlab)
 - [Documentation](https://www.terraform.io/docs/providers/gitlab/index.html)
 - [Issues](https://gitlab.com/gitlab-org/terraform-provider-gitlab/-/issues)
-- [Discord Server](https://discord.gg/CCc6Pe5EYy) 
+- [Discord Server](https://discord.gg/gitlab) 
 - [Terraform Provider Office Hour Call](https://www.meetup.com/gitlab-virtual-meetups/)