fix(ksonnet): don't depend on specific k8s version

[Duologic]

What this PR does / why we need it:
Loki should not depend on a specific k8s version (1.14), this would make upgrading clusters much harder.

As no imports are happening directly in this library, this change should be a no-op.

[codecov-commenter]

Codecov Report

Merging #2525 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2525      +/-   ##
==========================================
+ Coverage   63.56%   63.59%   +0.02%     
==========================================
  Files         163      163              
  Lines       14305    14305              
==========================================
+ Hits         9093     9097       +4     
+ Misses       4499     4497       -2     
+ Partials      713      711       -2     

Impacted Files	Coverage Δ
pkg/logql/evaluator.go	92.88% <0.00%> (+0.40%)	⬆️
pkg/ingester/transfer.go	64.82% <0.00%> (+1.37%)	⬆️

[pstibrany]

Thanks!

[owen-d]

I unfortunately think removing this breaks functionality for end users. Can you try installing from a fresh tanka according to the docs? I think this stems from the changes in https://github.com/grafana/loki/pull/2460/files which don't play nicely with the default versions used by tanka, but which we override internally. We'll also need to update the blurb in our docs (the prior deploying link), but I think this is important to sort out. Thanks for looking into it @Duologic

[Duologic]

Completely right, @owen-d. I've updated the docs accordingly.

We are actively working to get k8s-alpha to GA.

[Duologic]

Removed docs and added compatibility for envVar.

[owen-d]

Great, thanks!