Fix "concierge --version" when "go install"ed

[benhoyt]

Example:

$ go install github.com/canonical/concierge@v1.0.2
go: downloading github.com/canonical/concierge v1.0.2
$ concierge --version
concierge version dev (dev)

This should say concierge version v1.0.2.

It looks like the snap works fine:

$ which concierge
/snap/bin/concierge
$ concierge --version
concierge version 1.0.2 (a8143a89a4c2168a153a9260f18f455b966ad490)

[jnsgruk]

This is because the version in the snap is set by goreleaser at build time:

concierge/.goreleaser.yaml

Line 18 in a8143a8

- -X github.com/canonical/concierge/cmd.version={{ .Version }} -X github.com/canonical/concierge/cmd.commit={{ .Commit }}

[benhoyt]

Yeah, I figured as much. I'll probably switch to just having the version hard-coded in a Go file, like we now do with Pebble. It means to release you have to commit the version bump and then tag/release, but I think that's okay.

[dimaqq]

I'll give it a crack.
While we're at it, what do we want for local development, 1.10.0+dev?

[benhoyt]

Thanks! For Pebble we do -dev: https://github.com/canonical/pebble/blob/2f0fefac985fa2585a18096fb402cecaecd8e84b/cmd/version.go#L20

However, I'm not even too worried about that. No one really uses dev versions, so I'd be happy if we just left it as the previous version till we release the next.

I think this is going to be a small code tweak, but also a change to the release process and a section about how to do a release in the README.