Update gfx-hal requirement from 0.5 to 0.8

[dependabot]

Updates the requirements on gfx-hal to permit the latest version.

Changelog

Sourced from gfx-hal's changelog.

hal-0.8.0 (29-04-2021)

• Naga is the required and preferred shader translation path in Metal and OpenGL
• enabling SPIRV-Cross is optional behind cross feature API:
  • all backends can create shader modules from naga::Module
  • sampler reduction modes (min/max samplers)
  • image view creation requires image::Usage to be specified
  • timestamp period query is moved to the Queue
  • DescriptorLimits is added to consolidate descriptor-related limits and its fields changed from usize to u32
  • Limits and Capabilities structures merged together as PhysicalDeviceProperties
  • Entries for Mesh Shading and Descriptor Indexing added to PhysicalDeviceProperties
  • buffer descriptor indexing
  • sparse memory binding
  • blend color is renamed to blend constants
  • debug capture API for interfacing with XCode/RenderDoc/PIX
  • better shader and pipeline creation errors
• Infrastructure:
  • the new "bench" example is added
• Metal backend:
  • pipeline cache support with binary archives
  • profiling integration
  • immutable sampler support on Naga path
  • improve window resizing, expose "present with transaction" option

hal-0.7.0 (30-01-2021)

• Borrow and ExactSizeIterator bounds are removed from the iterators
• error improvements:
  • use thiserror for errors
  • variants and a few names are refactored
• API external synchronization constraints now match Vulkan, &mut changes affected the following parameters:
  • event in Device::set_event and Device::reset_event
  • fence in Device::reset_fences and Queue::submit
  • destination sets in write_descriptor_sets and copy_descriptor_sets
  • memory in map_memory and unmap_memory
  • queue in Queue::wait_idle
  • semaphore in Queue::present
• ImageFeature improvements:
  • new STORAGE_READ_WRITE bit, indicating that the storage can be read and written within the same draw/dispatch call
  • new TRANSFER_SRC and TRANSFER_DST bits, following VK_KHR_maintenance1
  • new SAMPLED_MINMAX bit, following VK_EXT_sampling_minmax
• Framebuffers become image-less, following VK_KHR_imageless_framebuffer
• the old swapchain model is removed, and the new one is updated to match the backends even better
• debug names are supported for all objectr
• other API changes:
  • bind_index_buffer now doesn't need a separate structure
  • plural versions of reset_fence and create_xx_pipeline are removed
  • swapchain images can be used for transfer operations
  • separate feature for comparison mutable samplers
  • pipeline descriptor vectors are replaced with slices
  • features for non-normalized mutable samplers

... (truncated)

Commits

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[dependabot]

Superseded by #317.