base_url required since (even for the public instance) v15.7.0

Bug Report

Since the new version of the provider, I have a merge request with the following changes:

 terraform {
   required_providers {
     gitlab = {
       source  = "gitlabhq/gitlab"
-      version = "3.20.0"
+      version = "15.7.0"
     }
     # plus other providers untouched
   }
 }

When the plan ran I got this error:

│ Error: Invalid provider configuration
│
│ Provider "registry.terraform.io/gitlabhq/gitlab" requires explicit
│ configuration. Add a provider block to the root module and configure the
│ provider's required arguments as described in the provider documentation.
│

The plan works if I define GITLAB_BASE_URL to https://gitlab.com/api/v4/.

Relevant Terraform Configuration

I use the public gitlab.com instance (therefor shouldn't need the base_url) and configure the token via GITLAB_TOKEN environment variable.

Relevant Log Output

Terraform v1.3.6
on linux_amd64
Initializing plugins and modules...
# lots of other resources getting refreshed
╷
│ Error: Invalid provider configuration
│
│ Provider "registry.terraform.io/gitlabhq/gitlab" requires explicit
│ configuration. Add a provider block to the root module and configure the
│ provider's required arguments as described in the provider documentation.
│
╵
╷
│ Error: No GitLab Base URL configured, either use the `base_url` provider argument or set it as `GITLAB_BASE_URL` environment variable
│
│   with provider["registry.terraform.io/gitlabhq/gitlab"],
│   on <empty> line 0:
│   (source code not available)
│
╵
Operation failed: failed running terraform plan (exit 1)

Additional Details

• GitLab Terraform Provider Version: 15.7.0
• GitLab Version: gitlab.com
• Terraform Version: 1.3.6