Update Travis config to install Bundler 1.17.3 (the most recent non-2.x version at time of writing) because Bundler 2.x is not compatible with Ruby < 2.3
Update Travis config to install Bundler 1.17.3 (the most recent non-2.x version at time of writing) because Bundler 2.x is not compatible with Ruby < 2.3

symbols-worldwide/symgate-gem