Updated cpal from 0.17.0 to 0.18.1.

[Eagisa]

Changes made to adapt to the new unified error API in 0.18.0:

• Replaced BuildStreamError, DefaultStreamConfigError, and PlayStreamError with the new unified cpal::Error type in error.rs
• Updated StreamError references to cpal::Error in desktop.rs and stream_manager.rs
• Updated StreamError variant matching to use the new ErrorKind API
• Fixed build_output_stream() to pass StreamConfig by value instead of by reference

Tested locally with no playback issues and all 98 tests pass.

[tesselode]

thank you!