Example can't run because of "Shadow map atlas" error

[happydpc]

Test on GTX 1070s, windows 10.

[2020-08-02T10:51:56Z ERROR gfx_backend_vulkan]
VALIDATION [VUID-VkImageViewCreateInfo-viewType-01004 (1838557948)] : Validation Error: [ VUID-VkImageViewCreateInfo-viewType-01004 ] Object 0: handle = 0xedbd50000000010, name = Shadow map atlas, type = VK_OBJECT_TYPE_IMAGE; | MessageID = 0x6d962afc | vkCreateImageView(): pCreateInfo->viewType can't be VK_IMAGE_VIEW_TYPE_CUBE_ARRAY without enabling the imageCubeArray feature. The Vulkan spec states: If the image cubemap arrays feature is not enabled, viewType must not be VK_IMAGE_VIEW_TYPE_CUBE_ARRAY (https://vulkan.lunarg.com/doc/view/1.2.141.0/windows/1.2-extensions/vkspec.html#VUID-VkImageViewCreateInfo-viewType-01004)
object info: (type: IMAGE, hndl: 1070683532407341072, name: Shadow map atlas)

[StarArawn]

@happydpc Thanks! This appears to be an issue with wgpu. I'll try to get a PR open to fix it.