[xmlunit/xmlunit.net] 101602: make Travis CI build "both" solutions

[Stefan B. <no...@gi...>]

  Branch: refs/heads/netstandard-2.0
  Home:   https://github.com/xmlunit/xmlunit.net
  Commit: 10160287318438e22568a05090eeadbf7994c396
      https://github.com/xmlunit/xmlunit.net/commit/10160287318438e22568a05090eeadbf7994c396
  Author: Stefan Bodewig <ste...@fr...>
  Date:   2019-04-04 (Thu, 04 Apr 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  make Travis CI build "both" solutions