Testing: Use Go modules and Start testing with go versions 1.11.x 1.12.x

[borisroman]

Library the master branch of kylelemons/godebug is unsupportive of Go version 1.9.x since https://github.com/kylelemons/godebug/commit/bde9f3c96d7aa052631925fa03b944627a335ff.

Travis is set to Go version 1.9.x hence it's not using Go modules (introduced in Go 1.11.x) and thus retrieving master of all dependencies when running go get.

This PR enables Travis to test with Go versions 1.11.x and 1.12.x, and starts using Go modules when testing.

[codecov-io]

Codecov Report

Merging #133 into master will decrease coverage by 0.09%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master     #133     +/-   ##
=========================================
- Coverage   69.03%   68.93%   -0.1%     
=========================================
  Files          98       98             
  Lines       10307    10254     -53     
=========================================
- Hits         7115     7069     -46     
+ Misses       2867     2865      -2     
+ Partials      325      320      -5

Impacted Files	Coverage Δ
hcl/hclsyntax/scan_string_lit.go	99.23% <0%> (+0.53%)	⬆️
hcl/hclsyntax/scan_tokens.go	98.46% <0%> (+1.31%)	⬆️

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[borisroman]

Hi @radeksimko @apparentlymart @pselle @jbardin,

Does one of you have time to take a look at this?

Thanks in advance,
Boris

[apparentlymart]

Hi @borisroman! Thanks for looking at this.

I'm a little nervous about upgrading all of the dependencies since that will ratchet forward anything that's depending on HCL and also depending on one of these packages.

Did you make that change because the tests were no longer passing after switching to newer Go versions? If so, I'd ideally like to find a smaller set of updates that fixes that problem just because then the risk to dependents when upgrading their HCL dependencies will be lower.

Switching the CI configuration to use a newer Go version is a great idea, though. If it would work to do that in isolation, without also upgrading all of the dependencies, I'd love to move forward with that and then approach the dependency updates a little more cautiously in separate PRs.

[borisroman]

Hi @apparentlymart

I've isolated the change to only include switching the CI configuration to use a newer Go version. It will work without updating the dependencies to their respective latest version.

Thanks for responding!

[apparentlymart]

Great, thanks @borisroman! I'm going to merge this now. (Sorry for the delay in getting back to you.)