139c62d762
This implements a simple way to upgrade Talos node running in maintenance mode (only if Talos is installed, i.e. if `STATE` and `EPHEMERAL` partitions are wiped). Upgrade is only available over SideroLink for security reasons. Upgrade in maintenance mode doesn't support any options, and it works without machine configuration, so proxy environment variables are not available, registry mirrors can't be used, and extensions are not installed. Fixes #6224 Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>