Switch to go modules

[rvolosatovs]

Switch to go modules to remove the glide dependency and simplify using of this library as a dependency.
Since the feature is opt-in in go 1.11, set GO111MODULE=on in Makefile
Merging this will break support for go versions pre-1.11
Refs #27
Closes #61

[rodaine]

Thanks for the patch! Adding the mod files is great but please leave the glide files in place for now, we still use it internally.

[rvolosatovs]

@rodaine any update on this?

[rvolosatovs]

@rodaine ☝️

[rvolosatovs]

Any chance this will be merged?

[tmc]

Refs #61

[jasonwzm]

What is the current status of this PR?

[rvolosatovs]

I haven't updated it for a while.
In case there is a real intent to merge it, I can check that everything is in order and update if necessary.

[rodaine]

Apologies for the delay. Yes, we still want to do this. Internally, we're in the process of migrating codebases from glide -> modules, so we can't remove the glide manifests yet, but getting the modules in place as the last of 0.x and then cutting v1 with modules alone is the plan.

Let me know if you need anything from me. This week, I will be focusing on our open source tools and getting through the backlogs.

[rvolosatovs]

Upgraded to Go 1.13.
Successfully rebased on latest master without merge conflicts.
Should be good to go, but I did only basic testing of the rebased version.

[rvolosatovs]

@rodaine any update on this?

[wozz]

any updates on this?

[rodaine]

Closed by #81