Update cluster.go help output (#266)

When reading the documentation, one may `--egress none` interpret to write `--egress ""` instead of `none` as none could mean to use an empty string.

The proposed approach is to add `"--egress none"` instead of `--egress none`, to have a visual border for the entire parameter.

Co-authored-by: Gerrit <[email protected]>

cmd/cluster.go

@@ -387,7 +387,7 @@ func newClusterCmd(c *config) *cobra.Command {
 	clusterUpdateCmd.Flags().BoolP("disable-pod-security-policies", "", false, "disable pod security policies")
 	clusterUpdateCmd.Flags().String("audit", "on", "audit logging of cluster API access; can be off, on or splunk (logging to a predefined or custom splunk endpoint).")
 	clusterUpdateCmd.Flags().String("purpose", "", fmt.Sprintf("purpose of the cluster, can be one of %s. SLA is only given on production clusters.", strings.Join(completion.ClusterPurposes, "|")))
-	clusterUpdateCmd.Flags().StringSlice("egress", []string{}, "static egress ips per network, must be in the form <networkid>:<semicolon-separated ips>; e.g.: --egress internet:1.2.3.4;1.2.3.5 --egress extnet:123.1.1.1 [optional]. Use --egress none to remove all egress rules.")
+	clusterUpdateCmd.Flags().StringSlice("egress", []string{}, "static egress ips per network, must be in the form <networkid>:<semicolon-separated ips>; e.g.: --egress internet:1.2.3.4;1.2.3.5 --egress extnet:123.1.1.1 [optional]. Use \"--egress none\" to remove all egress rules.")
 	clusterUpdateCmd.Flags().StringSlice("external-networks", []string{}, "external networks of the cluster")
 	clusterUpdateCmd.Flags().Duration("healthtimeout", 0, "period (e.g. \"24h\") after which an unhealthy node is declared failed and will be replaced. (0 = provider-default)")
 	clusterUpdateCmd.Flags().Duration("draintimeout", 0, "period (e.g. \"3h\") after which a draining node will be forcefully deleted. (0 = provider-default)")