* Update release number to 80.
Public Issues:
* Remove unused "`API Order`" term from glossary (public issue 657).
* Dynamically generate the extension appendix includes based on
information in `vk.xml`, including new metadata tags describing
deprecated, obsoleted, and promoted extensions (public pull request
690).
Internal Issues:
* Add valid usage statements to flink:vkCmdBindDescriptorSets to keep
offsets + range less than or equal to the buffer size (internal issue
1174).
New Extensions:
* `VK_EXT_conditional_render`
* `VK_KHR_create_renderpass2` (public issue 736)
* `VK_KHR_8bit_storage` (public issue 737)
Jon Leech