Roll vulkan-deps from d3d26aeb92d2 to 68f9998c8591 (4 revisions)

https://chromium.googlesource.com/vulkan-deps.git/+log/d3d26aeb92d2..68f9998c8591

Changed dependencies:
* vulkan-validation-layers: e4a3c3c66b..3a56790532

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/vulkan-deps-dawn-autoroll
Please CC kainino@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Dawn: https://bugs.chromium.org/p/dawn/issues/entry

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Bug: None
Tbr: kainino@google.com
Change-Id: Id0a6c7eee8278cce709475016e344e5339da0e76
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/116543
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -142,7 +142,7 @@ deps = {
   },
 
   'third_party/vulkan-deps': {
-    'url': '{chromium_git}/vulkan-deps@d3d26aeb92d2feb53fc15100dd1eca526b6239bb',
+    'url': '{chromium_git}/vulkan-deps@68f9998c859116b39267a71a4e2b6f4f01363965',
     'condition': 'dawn_standalone',
   },