The Welsh Governments FAQ's have answered it
Will professional sports fixtures, such as the rugby union autumn internationals or the EFL Championship matches, be allowed to continue during this period?
Yes, fixtures involving professional sportspeople are allowed to continue behind closed doors. All participants, such as players, officials, coaches, and broadcasters, are there in a working capacity.
Will professional or elite sports be allowed?
Sportspeople who work and earn a living through sport are allowed to continue working, and like everyone else they can leave home to do so if they cannot work from home.