[unity] updated changelog by added LWRP shader of last commit.

CHANGELOG.md

@@ -165,6 +165,7 @@
      
       The Project panel should now show an entry `Spine Lightweight RP Shaders` under `Packages`. If the directory is not yet listed, you will need to close and re-open Unity to have it display the directory and its contents.
     * **Usage:** The package provides two shaders specifically built for the lightweight render pipeline:
+      * `Lightweight Render Pipeline/Spine/Skeleton`, as a lightweight variant of the `Spine/Skeleton` shader,
       * `Lightweight Render Pipeline/Spine/Skeleton Lit`, as a lightweight variant of the `Spine/Skeleton Lit` shader and
       * `Lightweight Render Pipeline/Spine/Sprite`, as a lightweight variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders, which were not functioning in the lightweight render pipeline. The shaders can be assigned to materials as usual and will respect your settings of the assigned `LightweightRenderPipelineAsset` under `Project Settings - Graphics`.
     * **Restrictions** As all Spine shaders, the LWRP shaders **do not support `Premultiply alpha` (PMA) atlas textures in Linear color space**. Please export your atlas textures as `straight alpha` textures with disabled `Premultiply alpha` setting when using Linear color space. You can check the current color space via `Project Settings - Player - Other Settings - Color Space.`.