Add recent code-switching ASR papers and resources

[enesyugan]

Hi!

Thanks for maintaining this repository!

I came across it while looking for code-switching resources and thought I'd add a few papers that may be useful to the community.

This PR adds:

• Adding Robust Code-Switching Capabilities to High Performance Multilingual ASR
• Bayesian Low-Rank Factorization for Robust Model Adaptation
• Adapting Language Balance in Code-Switching Speech
• Weight Factorization and Centralization for Continual Learning in Speech Recognition
• PIER: A Novel Metric for Evaluating What Matters in Code-Switching
• Language-agnostic Code-Switching in Sequence-To-Sequence Speech Recognition
• DECM: Evaluating Bilingual ASR Performance on a Code-Switching/Mixing Benchmark

I also included links to the corresponding code repositories where available.

Some of the continual learning papers are a bit broader than code-switching, but they include experiments on code-switching ASR and have been useful in this context. If you think they are outside the scope of the repository, I'm happy to remove them.

Thanks!