add module_name provider metadata

[displague]

Fixes #252

Env TF_APPEND_USER_AGENT is also available.

[displague]

In some cases the module_name is being repeated in the User-Agent. I initially thought this would happen when Create and Update call Read, but:

With the following patch:

diff --git a/equinix/resource_metal_project.go b/equinix/resource_metal_project.go
index f546e2c4..9b6e0eee 100644
--- a/equinix/resource_metal_project.go
+++ b/equinix/resource_metal_project.go
@@ -176,7 +176,7 @@ func resourceMetalProjectRead(d *schema.ResourceData, meta interface{}) error {
 		return err
 	}
 	client.UserAgent = userAgent
-
+	fmt.Println("look here !!!!!!!!!!!!!", client.UserAgent)
 	proj, _, err := client.Projects.Get(d.Id(), nil)
 	if err != nil {
 		err = friendlyError(err)
diff --git a/equinix/resource_metal_project_acc_test.go b/equinix/resource_metal_project_acc_test.go
index ebae59cf..040d4e96 100644
--- a/equinix/resource_metal_project_acc_test.go
+++ b/equinix/resource_metal_project_acc_test.go
@@ -391,6 +391,11 @@ resource "equinix_metal_project" "foobar" {
 
 func testAccMetalProjectConfig_basic(r int) string {
 	return fmt.Sprintf(`
+	terraform {
+		provider_meta "equinix" {
+			module_name = "test"
+		}
+	}
 resource "equinix_metal_project" "foobar" {
     name = "tfacc-project-%d"
 }`, r)

I see the following:

=== CONT  TestAccMetalProject_importBasic
2022/09/29 20:10:54 [DEBUG] POST https://api.equinix.com/metal/v1/projects
look here !!!!!!!!!!!!! test test HashiCorp Terraform/1.3.0 (+https://www.terraform.io) Terraform Plugin SDK/2.9.0 terraform-provider-equinix/dev packngo/(devel)
2022/09/29 20:10:55 [DEBUG] GET https://api.equinix.com/metal/v1/projects/{id}