* Update release number to 124.
Github Issues:
* Fix Makefile SPECREMARK macro to work when not building in a git tree
(public issue 992).
* Ignore pname:aspectMask for unused attachments in
slink:VkSubpassDescription2KHR valid usage statements (public pull
request 1028).
* Minor markup / spelling fixes (public pull requests 1035, 1045).
Internal Issues:
* Fix markup in Valid Usage statement for slink:VkCreateFramebuffer
(internal issue 1823).
* Add a new <<synchronization-signal-operation-order, _signal operation
order_>> section to the synchronization chapter which describes in
detail the ordering guarantees provided by the API between fence and
semaphore signal operations (internal merge request 3368).
* Move generated `appendix/meta/` files into the Makefile GENERATED
directory (internal merge request 3381).
New Extensions
* `<<VK_KHR_shader_clock>>`
* `<<VK_KHR_timeline_semaphore>>`
* Update release number to 84.
Public Issues:
* Fix code sample in the `<<VK_EXT_debug_utils>>` extension (public issue
751).
* Fix misleading comment in `vk.xml` for
slink:VkDescriptorBufferInfo::pname:buffer (public pull request 762).
* Fix formatting of deprecation attributes in schema doc (public pull
request 767).
* Change `can` to `may` in the description of
elink:VkSparseImageFormatFlagBits, which are return values from queries
(public pull request 768).
* Prettify generated contact list in extension appendices, adding logos
and a New Issue link (public pull request 770).
* Enable sRGB conversion based on the image view format, not the image
format, in the <<textures-format-conversion, Format Conversion>> section
(public pull request 773).
* Fix typo in equation in the <<primsrast-lines-basic, Basic Line Segment
Rasterization>> section (public pull request 780).
* Fix special characters in GitHub contacts links (public pull request
783).
* Make clean_pdf target remove pdf folder (public pull request 784).
* Fix styleguide bad markup of block continuation (public pull request
792).
Other Issues:
* Allow a zero vertex attribute divisor in the
`<<VK_EXT_vertex_attribute_divisor>>` extension, exposed via the
slink:VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT feature.
* Add missing `structextends="VkDeviceCreateInfo"` to
slink:VkPhysicalDeviceShaderDrawParameterFeatures and
slink:VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT.
New Extensions:
* `VK_KHR_memory_model`
* `VK_EXT_astc_decode_mode`
* `VK_EXT_inline_uniform_block`
