containers: Add VERSION label to cockpit/ws
containers: Add VERSION label to cockpit/ws

cockpituous will replace the value on release:
https://github.com/cockpit-project/cockpituous/blob/master/release/release-dockerhub#L85

Fixes #13812
Closes #13813
martinpitt/cockpit,cockpituous/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,garrett/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpituous/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,deryni/cockpit,mvollmer/cockpit,deryni/cockpit,cockpituous/cockpit,martinpitt/cockpit,garrett/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,cockpit-project/cockpit,garrett/cockpit,mvollmer/cockpit,deryni/cockpit,moraleslazaro/cockpit,garrett/cockpit,deryni/cockpit,martinpitt/cockpit,deryni/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,cockpituous/cockpit,mvollmer/cockpit