Is "--add-protocol" for a zone not implemented?

**What would you like to be added**:
I want to manage des protocols of a zone by using this role.

`#> firewall-cmd --zone=block --add-protocol=ipv6-icmp`


**Why is this needed**:
For Ipv6 I want to add ipv6-icmp in an easy way.
https://firewalld.org/documentation/zone/options.html#protocol
