Fix gpu yuv conversion on godot-stable

[EgrorBs]

With this fix GPU YUV conversion needs rendering device and Godot 4.3+

Fixes #23

Tested on Godot-stable (4.2.2.stable.official.15073afe3) and Godot-latest (4.3.dev6.official.89850d553) on compat and forward+ renderers

[EIREXE]

I am very sorry for the delay, I was on vacation.

Do we need this anymore now that 4.3 has released?

[EgrorBs]

I hope you had a great vacation! :)

Personally, I think including this would improve compatibility, which is always a good thing, but it's totally up to you.

[juntaosun]

@EgrorBs I tested WebM transparent video, which contains BGRA channels, but after decoding with EIRTeam.FFmpeg, the pixels obtained only have BGR channels. The transparent pixels are lost.

`
yuv420p

yuva420p （transparent）
`
#38 (comment)

[juntaosun]

@EgrorBs Version v1.1.1 has been released and supports yuva. But it requires ffmpeg to be compiled with --enable-libvpx enabled. Can it be updated to compile an Android extension?

https://trac.ffmpeg.org/wiki/Encode/VP9

--enable-libvpx：  
To install FFmpeg with support for libvpx-vp9, look at the [Compilation Guides] 
 (https://ffmpeg.org/trac/ffmpeg/wiki/CompilationGuide) and compile FFmpeg with the option. Note that for 10-bit encoding,  
 you need to set the configuration option. --enable-libvpx--enable-vp9-highbitdepth