travis: add 1.x to go versions

[dvrkps]

No description provided.

[codecov]

Codecov Report

Merging #163 into master will increase coverage by 0.17%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #163      +/-   ##
==========================================
+ Coverage   84.55%   84.73%   +0.17%     
==========================================
  Files          41       41              
  Lines        5174     5174              
==========================================
+ Hits         4375     4384       +9     
+ Misses        636      630       -6     
+ Partials      163      160       -3

Impacted Files	Coverage Δ
feature_iter_string.go	89.51% <0%> (+0.69%)	⬆️
feature_iter_object.go	70.54% <0%> (+3.42%)	⬆️
feature_iter_skip.go	78.31% <0%> (+3.61%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 374e68a...f29a039. Read the comment docs.