Update vkrunner link in README
vkrunner repo was moved from github to the freedesktop gitlab. Update the link in the readme to reflect this change.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
vkrunner repo was moved from github to the freedesktop gitlab. Update the link in the readme to reflect this change.