hack: use >= for capi binaries version comparison

Only download the binaries if the existing binaries' version is lower
than the minimum version (currently 1.28.0). This change will be needed
when we copy etcd/kas binaries from existing container images which
build them from source.

Author: r4f4

hack/build-cluster-api.sh

@@ -28,9 +28,9 @@ copy_cluster_api_to_mirror() {
 
 sync_envtest() {
   if [ -f "${CLUSTER_API_BIN_DIR}/kube-apiserver" ]; then
-    version=$("${CLUSTER_API_BIN_DIR}/kube-apiserver" --version || echo "Kubernetes v0.0.0")
+    version=$("${CLUSTER_API_BIN_DIR}/kube-apiserver" --version | sed 's/Kubernetes //' || echo "v0.0.0")
     echo "Found envtest binaries with version: ${version}"
-    if [ "${version}" = "Kubernetes v${ENVTEST_K8S_VERSION}" ]; then
+    if printf '%s\n%s' v${ENVTEST_K8S_VERSION} "${version}" | sort -V -C; then
       return
     fi
   fi