[xmlunit/xmlunit] 864b8e: replace oraclejdk10 with openjdk10 in Travis build

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

  Branch: refs/heads/master
  Home:   https://github.com/xmlunit/xmlunit
  Commit: 864b8e8a4e30fa7d2f6c5442199dc50a55e2827f
      https://github.com/xmlunit/xmlunit/commit/864b8e8a4e30fa7d2f6c5442199dc50a55e2827f
  Author: Stefan Bodewig <ste...@fr...>
  Date:   2019-02-14 (Thu, 14 Feb 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  replace oraclejdk10 with openjdk10 in Travis build