[docs] Project classic is discontinued

See https://github.blog/changelog/2024-05-23-sunset-notice-projects-classic/

Signed-off-by: Olivier Tassinari <olivier.tassinari@gmail.com>

README.md

@@ -14,4 +14,4 @@ Feel free to open [a new GitHub issue](https://github.com/mui-org/mui-design-kit
 
 ## Roadmap
 
-Our [GitHub project's roadmap](https://github.com/mui-org/mui-design-kits/projects/1) is where you can learn about what features we're working on, what stage they're at, and when we expect to bring them to you.
+Our [GitHub project's roadmap](https://github.com/orgs/mui/projects/36) is where you can learn about what features we're working on, what stage they're at, and when we expect to bring them to you.