Update Travis builds

[ghost]

No description provided.

[codecov-io]

Codecov Report

Merging #767 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #767      +/-   ##
==========================================
- Coverage   85.73%   85.72%   -0.02%     
==========================================
  Files         159      159              
  Lines       15026    15028       +2     
==========================================
  Hits        12883    12883              
- Misses       2143     2145       +2

Impacted Files	Coverage Δ
lib/cosmos/utilities/ruby_lex_utils.rb	92.59% <100%> (+0.04%)	⬆️
lib/cosmos/io/json_drb.rb	98.69% <0%> (-0.66%)	⬇️
lib/cosmos/win32/win32.rb	22.27% <0%> (-0.12%)	⬇️

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[ghost]

@ryanatball I know we don't officially support Ruby 2.5 yet but this build passes. Let me know if you think we should merge.

[ghost]

👍 It's passing... We will need to support Ruby 2.5 soon anyways so looks good.