Upgrade spring boot 3.4

[cn-at-osmit]

Hi,

we had to upgrade our project to a supported spring boot release, so we had to get ssh-shell-spring-boot working with it.

This is the second PR (based on the #403 ) where we made the step between spring-boot 3.3.8 -> 3.4.2. It also updates spring-shell 3.3.4 -> 3.4.0.

All junit tests succeed and also some basic interactive tests are working.

Bye,
Chris

[johndemic]

Good stuff @cn-at-osmit ! This saved us a bunch of time. One minor thing I noticed is the ssh server doesn't actually start.
Our build is complicated and could certainly be some interaction with another starter we're using. I had to "manually" start it like this:

@Component
class ShellStartupListener(val server: SshServer) {

    val logger: Logger = LoggerFactory.getLogger(ShellStartupListener::class.java)

    @EventListener(ApplicationReadyEvent::class)
    fun onApplicationStartup() {
        if (!server.isStarted) {
            logger.warn("SSH server not started, starting it now")
            server.start()
        }
    }
}

I can provide more detail if necessary.