Add automatic deploy hooks to Travis config.

[artem-zinnatullin]

Continuation of #806, as far as I understand Travis doesn't run build if you just push a tag unless you add a deploy section, so I did that.

We can try to release 2.0.1 by tag as an experiment :)

See:

• https://docs.travis-ci.com/user/deployment
• https://docs.travis-ci.com/user/deployment/script/

[codecov-io]

Codecov Report

Merging #830 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #830   +/-   ##
=======================================
  Coverage   97.41%   97.41%           
=======================================
  Files          91       91           
  Lines        2707     2707           
  Branches      305      305           
=======================================
  Hits         2637     2637           
  Misses         38       38           
  Partials       32       32

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[nikitin-da]

👍