x11-libs/libXfixes: Revbump to 6.0.0

This also requires bumping x11-base/xorg-proto to 2021.4

BUG=none
TEST=emerge libXfixes

Change-Id: Ie5704b5ddb3f299fa9150992e6721551bd36b56d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2915043
Tested-by: Fergus Dall <sidereal@google.com>
Commit-Queue: Fergus Dall <sidereal@google.com>
Reviewed-by: David Riley <davidriley@chromium.org>
5 files changed