Merge branch 'ggeorgiev/select-k8s-deploy-branch' into 'main'

Deploy to Kubernetes cluster with KUBERNETES_DEPLOY_BRANCH condition

See merge request gitlab-org/gitlab-runner!5489



Merged-by: Georgi N. Georgiev <ggeorgiev@gitlab.com>
Approved-by: Hannes Hörl <2185075-hoegaarden@users.noreply.gitlab.com>