doc: update kernel version in sysfs-uevent ABI doc

We expect the changes described in ABI/testing/sysfs-uevent doc to appear in 4.13.
Signed-off-by: NPeter Rajnoha <prajnoha@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-uevent

 What:           /sys/.../uevent
 Date:           May 2017
-KernelVersion:  4.12
+KernelVersion:  4.13
 Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
 Description:
                 Enable passing additional variables for synthetic uevents that