* Add ruby 2.6 test * Fix broken tests * Fix compatibility test * Fix bundler version * Use new docker image * Fix broken test * Use new docker image in ruby26 test * Install ruby for mac
* Add ruby 2.3, 2.4 and 2.5 test for linux. * Update kokoro files * Add back commented gc test * Fix gc_test failure * Remove unused code * Update ruby 2.5.0 to 2.5.1 * Update ruby 2.3 to 2.3.8 * Remove useless comment