feat(libplacebo): added Vulkan device selection for libplacebo

Signed-off-by: k4yt3x <i@k4yt3x.com>

include/libvideo2x/libplacebo.h

@@ -9,13 +9,13 @@ extern "C" {
 }
 
 int init_libplacebo(
-    AVBufferRef *hw_ctx,
     AVFilterGraph **filter_graph,
     AVFilterContext **buffersrc_ctx,
     AVFilterContext **buffersink_ctx,
     AVCodecContext *dec_ctx,
     int out_width,
     int out_height,
+    uint32_t vk_device_index,
     const std::filesystem::path &shader_path
 );