3x/turris-version: update to version 3.11.22

PR with notification for 3.11.22.

I think that we should also create another errata entry https://doc.turris.cz/doc/en/troubleshooting/erratum

My suggestion:

Affected Turris OS: 3.11.20
PPTP VPN network stopped working

TurrisOS 3.11.20 updated disabled automatic conntrack helper assignment in /etc/sysctl.conf because of CVE-2020-28041. This can break PPTP VPN network.

To fix this issue enable net.netfilter.nf_conntrack_helper=1 in  /etc/sysctl.conf and install kmod-nf-nathelper-extra

What do you think @jschlehofer ?