Update provider to use newest group name validation from v2.18.0

[BrunoQuaresma]

From user:

I noticed this limitation was removed on Coder v2.18.0, but the TF provider v0.0.8 still uses v2.17.x validation rules:
https://github.com/coder/terraform-provider-coderd/blob/v0.0.8/go.mod#L7
https://github.com/coder/terraform-provider-coderd/blob/v0.0.8/internal/codersdkvalidator/group_name.go#L9

[BrunoQuaresma]

It is already updated on main but it requires a release.

[ethanndickson]

Thanks for the heads up, release is live!