Updated Travis CI configuration
Updated Travis CI configuration

- added PHP 7.3 builds
- removed installing zend-mvc-console as it is now dev dependency
  (as we support only zend-mvc we need it as dev dependency)
- removed updating composer (it is done by travis itself)
- removed sudo: false
- removed redundant env variable LEGACY_DEPS

doctrine/DoctrineORMModule,doctrine/DoctrineORMModule,doctrine/DoctrineORMModule