Update Vulkan-Headers to version 1.1.154 to include VK_KHR_portability_subset.
diff --git a/ExternalRevisions/Vulkan-Headers_repo_revision b/ExternalRevisions/Vulkan-Headers_repo_revision
index d347369..77ca791 100644
--- a/ExternalRevisions/Vulkan-Headers_repo_revision
+++ b/ExternalRevisions/Vulkan-Headers_repo_revision
@@ -1 +1 @@
-83825d55c7d522931124696ecb07ed48f2693e5c
+7f9879b1b1fab53f719a9ed5e6e29533b10972b2