Bump code-server to 4.15.0

codehub/Chart.lock

codehub/Chart.yaml

codehub/templates/_helpers.tpl

codehub/templates/hub/configmap.yaml

codehub/templates/hub/deployment.yaml

codehub/templates/hub/pdb.yaml

codehub/templates/proxy/deployment.yaml

codehub/templates/proxy/pdb.yaml

codehub/templates/proxy/service-account.yaml

codehub/templates/singleuser/networkpolicy.yaml

codehub/values.yaml

dockerfiles/code-server/Dockerfile