Auto merge of #1176 - JerryShih:update-yuv-color-space-enum, r=kvark
Auto merge of #1176 - JerryShih:update-yuv-color-space-enum, r=kvark

Add #[repr(u32)] for YuvColorSpace enum.

r? @glennw @kvark
The cbindgen needs this to generate the proper c binding enum code.
If I don't have the u32 type, I only see the forward declaration in the generated header.

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