Align wgpu_types::CompositeAlphaMode serde serializations to spec (#4940)

* Align wgpu_types::CompositeAlphaMode serde serializations to spec

* add changelog

CHANGELOG.md

@@ -179,6 +179,7 @@ Passing an owned value `window` to `Surface` will return a `Surface<'static>`. S
 #### General
 
 - `BufferMappedRange` trait is now `WasmNotSendSync`, i.e. it is `Send`/`Sync` if not on wasm or `fragile-send-sync-non-atomic-wasm` is enabled. By @wumpf in [#4818](https://github.com/gfx-rs/wgpu/pull/4818)
+- Align `wgpu_types::CompositeAlphaMode` serde serialization to spec. By @littledivy in [#4940](https://github.com/gfx-rs/wgpu/pull/4940)
 
 #### Vulkan
 

wgpu-types/src/lib.rs

@@ -4992,7 +4992,7 @@ pub enum PresentMode {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "trace", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
-#[cfg_attr(feature = "serde", serde(rename_all = "camelCase"))]
+#[cfg_attr(feature = "serde", serde(rename_all = "lowercase"))]
 pub enum CompositeAlphaMode {
     /// Chooses either `Opaque` or `Inherit` automatically，depending on the
     /// `alpha_mode` that the current surface can support.