Merge pull request #1157 from Unity-Technologies/fix-depthcopy

Disable color writes in copydepth shader, fixes Vulkan Sceneview in HDRP

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/CopyDepthBuffer.shader

             ZTest  Always
             ZWrite On
             Blend  Off
+            ColorMask 0
 
             HLSLPROGRAM
             #pragma target 4.5