Also reported on GitHub:
https://github.com/openSUSE/transactional-update/issues/70

On my MicroOS Kubic systems running systemd-resolved, any calls to
transactional-update fail, as the `/run/systemd/resolve` directory can't be
copied into the snapshot:

```
# transactional-update shell
Checking for newer version.
transactional-update 3.5.2 started
Options: shell
Separate /var detected.
2021-09-09 18:09:29 tukit 3.5.2 started
2021-09-09 18:09:29 Options: -c129 open 
2021-09-09 18:09:30 Using snapshot 129 as base for new snapshot 130.
2021-09-09 18:09:30 Syncing /etc of previous snapshot 128 as base into new
snapshot "/.snapshots/130/snapshot"
2021-09-09 18:09:31 Discarding snapshot 130.
ERROR: filesystem error: cannot copy: Operation not supported
[/run/systemd/resolve] [/.snapshots/130/snapshot/run/systemd/resolve]
transactional-update finished
```

Steps to reproduce:

In a fresh MicroOS instance, replace wicked with systemd-resolved using a
series of commands like this:

```
transactional-update shell
zypper install systemd-network
systemctl disable wicked.service
# disable DNSSEC globally
sed -i '/^#\?DNSSEC=/{s/^#//;s/=.*$/=no/}' /etc/systemd/resolved.conf
systemctl enable systemd-networkd.service systemd-resolved.service
ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
echo '[Match]
Type=ether

[Network]
DHCP=yes
DNSOverTLS=opportunistic

[DHCPv4]
UseDomains=yes
RouteMetric=10

[DHCPv6]
RouteMetric=10
' > /etc/systemd/network/80-dhcp.network
```

Reboot and attempt `transactional-update shell` again. The command fails.