CI Failed in resolving requirements.

[alisharpasand]

CI script fails to resolve requirements cause it can't find gem bundler.

https://travis-ci.org/leereilly/swot/builds/628779092

Here's a part of the log:

Could not find gem 'bundler (~> 1.5)' in any of the relevant sources:
  the local ruby installation�[0m

�[31;1mThe command "eval bundle install --jobs=3 --retry=3 " failed. Retrying, 3 of 3.�[0m

Fetching gem metadata from http://rubygems.org/.........
Fetching gem metadata from http://rubygems.org/.
Resolving dependencies...
�[31mBundler could not find compatible versions for gem "bundler":
  In Gemfile:
    bundler (~> 1.5)

  Current Bundler version:
    bundler (2.1.2)
This Gemfile requires a different version of Bundler.
Perhaps you need to update Bundler by running `gem install bundler`?

Could not find gem 'bundler (~> 1.5)' in any of the relevant sources:
  the local ruby installation�[0m

�[31;1mThe command "eval bundle install --jobs=3 --retry=3 " failed 3 times.�[0m

travis_time:end:02449070:start=1577116924379508233,finish=1577116933808081318,duration=9428573085,event=install
�[0K�[31;1mThe command "bundle install --jobs=3 --retry=3" failed and exited with 6 during .�[0m

Your build has been stopped.