Remove CRI v1alpha2

After the removal of dockershim we can finally also drop support for CRI
v1alpha2.

Signed-off-by: Sascha Grunert <sgrunert@redhat.com>

hack/update-generated-runtime-dockerized.sh

@@ -25,7 +25,7 @@ KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
 KUBE_REMOTE_RUNTIME_ROOT="${KUBE_ROOT}/staging/src/k8s.io/cri-api/pkg/apis/runtime/"
 source "${KUBE_ROOT}/hack/lib/init.sh"
 
-runtime_versions=("v1alpha2" "v1")
+runtime_versions=("v1")
 
 kube::golang::setup_env