[docs] Update GitHub project links (#41370)

docs/pages/blog/2023-material-ui-v6-and-beyond.md

@@ -69,7 +69,7 @@ Expect to hear more about that towards the end of Q2 '24.
 ## Follow along and contribute
 
 We've consolidated the v6 changes in [this GitHub issue](https://github.com/mui/material-ui/issues/30660)—please feel free to chime in and participate in the discussions!
-You can also always check the [public Material UI GitHub project](https://github.com/mui/material-ui/projects/26) to see the planned releases and their respective umbrella issues.
+You can also always check the [Material UI GitHub project](https://github.com/orgs/mui/projects/23/views/12) to see the planned releases and their respective umbrella issues.
 
 We hope you're as excited as we are about these changes!
 Have a wonderful holiday season and a Happy New Year! 🎉

docs/pages/blog/mui-core-v5.md

@@ -701,9 +701,9 @@ We hope we can reach 50% of the React community by 2026. This is an ambitious go
 
 ### A public roadmap
 
-You can use our public roadmap on GitHub to learn about what features we're working on, what stage they're at, and when we expect to bring them to you:
+You can use the GitHub projects to learn about what features we're working on, what stage they're at, and when we expect to bring them to you:
 
-- [MUI Core](https://github.com/mui/material-ui/projects/25)
+- [MUI Core](https://github.com/mui/material-ui/projects?query=is:open)
 - [MUI X](https://github.com/mui/mui-x/projects/1)
 
 We offer this transparency into what we plan to work on so that you can plan better and share feedback earlier to influence what we're building.