adds hashicorp/assert to list of official providers

[ksatirli]

Hey JetBrains folks 👋🏼

Kerim here, big fan of the Terraform plugin inside GoLand.

I wanted to update this list with the Assert provider @bschaatsbergen and others maintain at https://registry.terraform.io/providers/hashicorp/assert/latest.

Hope this PR makes sense!

[bschaatsbergen]

Thanks for this @ksatirli. Would be great if we could add this provider to the IntelliJ-HCL plugin 👍🏼.