Associates a CIDR block with your subnet. You can only associate a single IPv6 CIDR block with your subnet. An IPv6 CIDR block must have a prefix length of /64.
ec2_associate_subnet_cidr_block(Ipv6CidrBlock, SubnetId)
[required] The IPv6 CIDR block for your subnet. The subnet must have a /64 prefix length.
[required] The ID of your subnet.
svc$associate_subnet_cidr_block( Ipv6CidrBlock = "string", SubnetId = "string" )