refactor: migrate gitlab_project_tag to Framework

Relates to issue #6694 (closed)

Changes

This MR migrates the gitlab_project_tag resource from Terraform Plugin SDK to Terraform Plugin Framework.

New Files Created:

• internal/provider/resource_gitlab_project_tag.go - Framework-based resource implementation

  • Implements resource.Resource, resource.ResourceWithConfigure, and resource.ResourceWithImportState interfaces
  • Complete CRUD operations (Create, Read, Update, Delete)
  • Proper schema definition with all attributes: id, name, project, ref, message, protected, target, release, commit
  • Nested objects for Release and Commit using SetNestedAttribute
  • Two-part ID format: <project>:<tag_name>
  • Helper function modelToStateModel() for state management

• internal/provider/resource_gitlab_project_tag_test.go - Framework-based acceptance tests

  • TestAccGitlabProjectTag_basic test covering create, import, and update scenarios
  • Helper functions for destroy checks, existence verification, and attribute validation
  • Proper test isolation using testutil.CreateProject and testutil.CreateBranches

Files Modified:

• internal/provider/sdk/resource_gitlab_project_tag.go - Replaced with migration notice comment
• internal/provider/sdk/resource_gitlab_project_tag_test.go - Replaced with migration notice comment
• internal/provider/sdk/schema_gitlab_project_tag.go - Replaced with migration notice comment

Key Implementation Details:

• Immutable Tags: No Update function needed - all attributes use RequiresReplace plan modifier since tags are immutable in GitLab API
• Two-Part ID Format: Resource ID is <project>:<tag_name> using utils.BuildTwoPartID and utils.ParseTwoPartID
• Ref Attribute: Only set during Create, not available after import (consistent with branch resource pattern)
• Nested Objects: Release and Commit are SetNestedAttribute objects that may be null
• Time Formatting: Commit dates use time.RFC3339 format
• Error Handling: 404 errors in Read function remove resource from state
• Auto-Registration: Uses init() function with registerResource() to auto-register with provider

Testing:

The migration follows patterns established in similar resources like resource_gitlab_branch.go and maintains backward compatibility for users upgrading from the SDK version.