Refactor sitemap generation and linking functionality. The changes were made to improve the flexibility and reusability of the code, allowing for dynamic sitemap filenames and routes.

[thejmitchener]

Focuses on refactoring the sitemap generation and linking functionality to improve flexibility and reusability of the code. The changes allow for dynamic sitemap filenames and routes, enhancing the overall usability of the sitemap feature.

Specifically, the changes in the code include:

• Updating the README.md file to include instructions on linking to the sitemap with dynamic filenames.
• Refactoring the SitemapController.php to remove the hardcoded default filename and make the filename parameter required for better flexibility.
• Modifying the SitemapServiceProvider.php to adjust the route definition to accept dynamic filenames and ensure they end with ".xml".

These changes enhance the codebase by making the sitemap generation and linking functionality more adaptable and reusable, ultimately improving the project's maintainability and efficiency.