Remove sudo setting from travis.yml

[sekky0905]

Change

Remove sudo: false setting from travis.yml .

Context

According to the following posts, Travis-CI had two Linux infrastructures which are containers and virtual machines, but recently Travis-CI was combined two Linux infrastructures into a virtual machine-based Linux infrastructures.

https://blog.travis-ci.com/2018-11-19-required-linux-infrastructure-migration
https://blog.travis-ci.com/2018-10-04-combining-linux-infrastructures

Now Container-based environment is duplicated.

Build Environment Overview - Travis CI

If you currently specify sudo: false in your .travis.yml, we recommend removing that configuration soon.

quoted by
https://blog.travis-ci.com/2018-11-19-required-linux-infrastructure-migration

[codecov-io]

Codecov Report

Merging #167 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #167   +/-   ##
=======================================
  Coverage   91.25%   91.25%           
=======================================
  Files          13       13           
  Lines         720      720           
=======================================
  Hits          657      657           
  Misses         44       44           
  Partials       19       19

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[l3pp4rd]

Thanks ;)