Add default branch protection workaround text to project

Added documentation to the `gitlab_project` resource describing a workaround to allow Terraform to manage the default branch protection on a project.

Author: beekeep

docs/resources/project.md

@@ -5,6 +5,12 @@ subcategory: ""
 description: |-
   The gitlab_project resource allows to manage the lifecycle of a project.
   A project can either be created in a group or user namespace.
+  -> Default Branch Protection Workaround Projects are created with default branch protection.
+  Since this default branch protection is not currently managed via Terraform, to workaround this limitation,
+  you can remove the default branch protection via the API and create your desired Terraform managed branch protection.
+  In the gitlab_project resource, define a local-exec provisioner which invokes
+  the /projects/:id/protected_branches/:name API via curl to delete the branch protection on the default
+  branch using a DELETE request. Then define the desired branch protection using the gitlab_branch_protection resource.
   Upstream API: GitLab REST API docs https://docs.gitlab.com/ce/api/projects.html
 ---
 
@@ -14,6 +20,13 @@ The `gitlab_project` resource allows to manage the lifecycle of a project.
 
 A project can either be created in a group or user namespace.
 
+-> **Default Branch Protection Workaround** Projects are created with default branch protection. 
+Since this default branch protection is not currently managed via Terraform, to workaround this limitation, 
+you can remove the default branch protection via the API and create your desired Terraform managed branch protection.
+In the `gitlab_project` resource, define a `local-exec` provisioner which invokes 
+the `/projects/:id/protected_branches/:name` API via curl to delete the branch protection on the default 
+branch using a `DELETE` request. Then define the desired branch protection using the `gitlab_branch_protection` resource.
+
 **Upstream API**: [GitLab REST API docs](https://docs.gitlab.com/ce/api/projects.html)
 
 ## Example Usage

internal/provider/resource_gitlab_project.go

@@ -644,6 +644,13 @@ var _ = registerResource("gitlab_project", func() *schema.Resource {
 
 A project can either be created in a group or user namespace.
 
+-> **Default Branch Protection Workaround** Projects are created with default branch protection. 
+Since this default branch protection is not currently managed via Terraform, to workaround this limitation, 
+you can remove the default branch protection via the API and create your desired Terraform managed branch protection.
+In the ` + "`gitlab_project`" + ` resource, define a ` + "`local-exec`" + ` provisioner which invokes 
+the ` + "`/projects/:id/protected_branches/:name`" + ` API via curl to delete the branch protection on the default 
+branch using a ` + "`DELETE`" + ` request. Then define the desired branch protection using the ` + "`gitlab_branch_protection`" + ` resource.
+
 **Upstream API**: [GitLab REST API docs](https://docs.gitlab.com/ce/api/projects.html)`,
 
 		CreateContext: resourceGitlabProjectCreate,