Add Parallel WaveGAN discriminator

[Yuan-ManX]

✨ Description

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🚧 Related Issues

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👨‍💻 Changes Proposed

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🧑‍🤝‍🧑 Who Can Review?

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🛠 TODO

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✅ Checklist

• Code has been reviewed
• Code complies with the project's code standards and best practices
• Code has passed all tests
• Code does not affect the normal use of existing features
• Code has been commented properly
• Documentation has been updated (if applicable)
• Demo/checkpoint has been attached (if applicable)

[lmxue]

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