Log current version when checking for updates

[scottyeager]

Currently, Zos does not log its current version in an ongoing fashion. The version is logged at time of boot, and if I recall correctly also during updates.

It would be helpful to include the current version number when this log is generated:

zos/pkg/upgrade/upgrade.go

Line 195 in dbae7a5

log.Info().Str("after", next.String()).Msg("checking for update after")

That way, it will be easy to scan the logs and determine which version a node is running.