Updates to volk, vulkan headers, `vk_enum_string_helper.h`, VMA,
glslang, spirv-reflect.
VMA doesn't tag SDK releases specifically, and still hasn't had a tagged
release since 3.0.1, but the Vulkan SDK now seems to ship a recent master
commit, so we do the same.
Actually sdk-1.2.154.1 for Vulkan-Loader.
glslang is updated to bacaef3237c515e40d1a24722be48c0a0b30f75f which is the
known-good version for Vulkan-ValidationLayers 1.2.154.0.
COPYRIGHT.txt was synced with the current version of the glslang LICENSE.txt,
and `glslang/register_types.cpp` now uses the upstream definition for its
default builtin resource instead of hardcoding it.
Rémi Verschelde