chore(beep boop 🤖): Bump `MCORE_TAG=9a75c72...` (2024-11-25)
🚀 PR to bump `NVIDIA/Megatron-LM` in `Dockerfile.ci` to `MCORE_TAG=9a75c72f7b41e1e74322827be466d56dec53ccce`.  

📝 Please remember the following to-do's before merge: 
- [ ] Verify the presubmit CI  

🙏 Please merge this PR only if the CI workflow completed successfully.