Simplerule: wrong IP protocol version filter statement for IPv6 traffic

[nbarrientos]

nftables::simplerule{"foo":
  action => 'accept',
  proto  => 'tcp6',
  dport  => 666,
}

Generates:

inet filter default_in ip version 6 tcp dport { 666 } accept

which is wrong. It should be:

inet filter default_in ip6 version 6 tcp dport { 666 } accept

Otherwise the IPv6 traffic is not matched and hence rejected:

kernel: [nftables] INPUT Rejected: IN=eth0 OUT= MACSRC=X MACDST=X MACPROTO=86dd SRC=FOO DST=BAR LEN=80 TC=0 HOPLIMIT=58 FLOWLBL=791055 PROTO=TCP SPT=41896 DPT=666 SEQ=3478527298 ACK=0 WINDOW=64800 RES=0x00 SYN URGP=0 OPT (020405A00402080AF96995530000000001030307)

Trivial fix to apply here:

https://github.com/voxpupuli/puppet-nftables/blob/master/templates/simplerule.epp#L18

Tests to be fixed accordingly.