v2.0.0 Release

Release 2.0.0. Updates include:

• Added chowdsp_plugin_state for managing plugin state.
• Added enumerate and zip iterators.
• Added CLAP note name support to chowdsp::SynthBase.
• Added TupleHelpers::visit_at.
• Added chowdsp::OptionalPointer.
• Added chowdsp::toString() for converting std::string_view to juce::String.
• Added chowdsp::HostContextProvider for connecting UI elements to host parameter context info.
• Added chowdsp::TweaksFile for prototyping and fine-tuning with live changes.
• Added chowdsp::Rectangle: a constexpr-capable clone of juce::Rectangle.
• Improved const-correctness of chowdsp::BufferView.
• Improved flexibility for saving/loading JSON objects.