build(deps): bump github.com/spf13/viper from 1.20.0 to 1.20.1

Bumps [github.com/spf13/viper](https://github.com/spf13/viper) from 1.20.0 to 1.20.1.
- [Release notes](https://github.com/spf13/viper/releases)
- [Commits](https://github.com/spf13/viper/compare/v1.20.0...v1.20.1)

check for nil desc.Metadata before attempting to unmarshall, avoiding…

If 'truncate' fails for /etc/machine-id during 'commit', attempt with…

doc: document VIRTER_ACCESS_NETWORK

virter: pass-through exit code from provisioning

When a provisioning step fails, it may be helpful to the caller of
virter to know the exit code of the script.

So, if an SSH or container provisioning step fails with an exit code,
pass it through to the CLI, exiting from the virter process with the
same exit code.

virter: add pool option to Disk

We may want to attach "dynamic" disks to a VM that are stored in a
different storage pool than the default one.

So allow users to specify a "pool=..." option on the command line, which
changes the storage location of the disk to the specified pool.

cmd: allow log level to be set with an environment variable

This is not a config key because logging is used while loading the
config.

Set ssh_ping_timeout default to 5 minutes.

Since Windows has to be rebooted when the hostname is
changed, provisioning may take longer than one minute.

Signed-Off-By: Johannes Thoma <[email protected]>

Release 0.23.0

Release 0.22.0