Release for Vulkan SDK 1.1.126

• Add support for Metal 3.0 capabilities.
• Add support for extensions:
  • VK_EXT_swapchain_colorspace (iOS, already supported on macOS).
  • VK_EXT_hdr_metadata (macOS)
• Use native texture swizzling when available.
• Set default value of the MVK_ALLOW_METAL_FENCES environment variable to 1 (true),
  to enable use of MTLFence for Vulkan semaphores, by default.
• Support additional capabilities in 1D images, including rendering, clearing,
  and mipmaps. Add MVK_CONFIG_TEXTURE_1D_AS_2D environment variable to
  enable/disable these capabilities.
• Use placement MTLHeaps for VkDeviceMemory when possible.
• Report heap sizes accurately when possible.
• Add support for additional colorspace options.
• Add support for the VkPhysicalDeviceFeatures::shaderResourceMinLod feature.
• Add support for compressed 3D images on macOS.
• Update MoltenVK_Runtime_UserGuide.md about embedding libMoltenVK.dylib in an application.
• Clarify static linking as the recommended linking approach for iOS app store distribution.
• Add request for feedback from people who reject MoltenVK to README.md document.
• Allow MVK_CONFIG_SYNCHRONOUS_QUEUE_SUBMITS build setting to be overridden.
• Fix memory leaks of system classes during VkInstance and VkQueue creation.
• Fix memory leaks when compiling shaders and pipelines without default OS autorelease pool.
• Fix severe FPS degradation caused by certain swapchain recreation situations.
• Log format substitution error when MTLPixelFormatDepth24Unorm_Stencil8 is not supported.
• Reduce memory usage by adjusting default memory allocs for many MVKVectorInline uses and
  replacing use of MVKVectorDefault with std::vector in descriptor set bindings.
• Set value of VkPhysicalDeviceLimits::maxTexelBufferElements to more realistic value.
• Add linking separate shader texts to GLSLToSPRIVConverter.
• Move generation of SPIRV-Cross/mvkSpirvCrossRevisionDerived.h to separate script.
• Support Xcode 11.1.
• Update dependency libraries to match Vulkan SDK 1.1.126.
• Update to latest SPIRV-Cross version:
  • MSL: Support option for treating 1D textures as 2D textures of height 1.
  • MSL: Fix array copies to/from interpolators.
  • MSL: Fix 16-bit integer literals.
  • MSL: Fix regression with OpCompositeConstruct from std140 float[].
  • Fixes cases where discard and demote are called in pure functions
    and the function result is not consumed.
  • Do not consider aliased struct types if the master is not a block.
  • Fix OpVectorExtractDynamic with spec constant op index.
  • Update SPIR-V headers to SPIR-V 1.5.