test: example bug feature

[davidalpert]

demonstrates #89

fails with:

  Scenario:                                                          # features/git-mob/bugs/89-co-authors-not-cleared-from-message-template-when-returning-to-git-solo.feature:30
    Given I successfully run `git mob ad`                            # aruba-2.0.0/lib/aruba/cucumber/command.rb:10
    And the file "~/.gitmessage" should contain:                     # aruba-2.0.0/lib/aruba/cucumber/file.rb:157
      """

      Co-authored-by: Amy Doe <amy@findmypast.com>
      """
    When I successfully run `git solo`                               # aruba-2.0.0/lib/aruba/cucumber/command.rb:10
    And the file "~/.gitmessage" should not contain "Co-authored-by" # aruba-2.0.0/lib/aruba/cucumber/file.rb:148
      expected "\n\nCo-authored-by: Amy Doe <amy@findmypast.com>" not to have file content: string includes: "Co-authored-by" (RSpec::Expectations::ExpectationNotMetError)
      features/git-mob/bugs/89-co-authors-not-cleared-from-message-template-when-returning-to-git-solo.feature:38:in `the file "~/.gitmessage" should not contain "Co-authored-by"'