Add entry in CHANGELOG.md

Author: opstic

CHANGELOG.md

@@ -166,6 +166,8 @@ By @cwfitzgerald in [#8162](https://github.com/gfx-rs/wgpu/pull/8162).
 
 - Added support for external textures based on WebGPU's [`GPUExternalTexture`](https://www.w3.org/TR/webgpu/#gpuexternaltexture). These allow shaders to transparently operate on potentially multiplanar source texture data in either RGB or YCbCr formats via WGSL's `texture_external` type. This is gated behind the `Features::EXTERNAL_TEXTURE` feature, which is currently only supported on DX12. By @jamienicol in [#4386](https://github.com/gfx-rs/wgpu/issues/4386).
 
+- Added support for transient textures on Metal and Vulkan, gated behind the `Features::TRANSIENT_ATTACHMENTS` feature. By @Opstic in [#8247](https://github.com/gfx-rs/wgpu/pull/8247)
+
 ### Changes
 
 #### General