Use cobra zsh gen

[rsteube]

Sadly the PR concerning zsh completion is still not merged yet, but i managed to extract the changes to a separate package.
This way lab does not need to depend on a cobra fork anymore but instead just has to add an additional dependency (https://github.com/rsteube/cobra-zsh-gen).

[zaquestion]

Nice touch!

[rsteube]

The zsh PR is now merged. Opened a new PR for the custom completions.
If that succeeds soon we might as well switch directly to the new version and skip this PR.

[zaquestion]

Just seeing this, sounds good, LMK what route you wanna take and we'll do that.

[rsteube]

Let's be optimistic for now.

[rsteube]

@zaquestion In the light of spf13/cobra#959 i unarchived https://github.com/rsteube/cobra-zsh-gen and think we should reopen this PR.

Have a look at the go.mod, i executed go mod tidy and it seems quite some entries were removed by that.

[zaquestion]

@rsteube Feel free to reopen (I think you'll need to open new), as long as you merge/rebase in master and do a build with modules enabled it should resolve how the go.mod works out.

At least it won't let me reopen as it says the branch has been force pushed (so if you already rebased or some such thats probably why)