base_url validation doesn't allow valid TLDs

[simontabor]

https://github.com/tdabasinskas/terraform-provider-backstage/blob/main/backstage/provider.go#L61

.engineer is a valid TLD and the regex fails, preventing use of the plugin.

I don't think validating URLs is terribly useful for this provider, especially not using regex - an invalid URL can simply be allowed to result in errors further down the line (connection failure)

Reproduce

provider "backstage" {
  base_url = "https://my-backstage-instance.engineer"
}

│ Error: Invalid Attribute Value Match
│
│   with provider["registry.terraform.io/tdabasinskas/backstage"],
│   on main.tf line 51, in provider "backstage":
│   51:   base_url = "https://my-backstage-instance.engineer"
│
│ Attribute base_url must be a valid URL, got: https://my-backstage-instance.engineer

[simontabor]

Using BACKSTAGE_BASE_URL bypasses the validation and allows it to proceed, which is a separate issue (it should be validated in the same way), but this allows me to proceed for now.

[tdabasinskas]

Sounds legit. Thanks for reporting these - will try to address then.