[task/github-readme/travis] Fix Travis-Badge and link

PHPBB3-11968
Merge branch 'task/github-readme/travis' into develop-olympus

* task/github-readme/travis:
  [task/github-readme/travis] Fix Travis-Badge and link
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [task/github-readme/travis] Fix Travis-Badge and link