Bump ruby versions to 2.5.5 and 2.6.2.

[iliabylich]

Closes #561 and #562

[whitequark]

@iliabylich I think you should be able to release yourself now.

[iliabylich]

@whitequark Bump version (to 2.6.2.0 in our case) and rake release? Nothing special?

[whitequark]

Yep, just that.

[iliabylich]

Nope, still doesn't work:

Couldn't git push. `git push ' failed with the following output:

remote: error: GH006: Protected branch update failed for refs/heads/master.
remote: error: Required status check "continuous-integration/travis-ci" is expected. At least 1 approving review is required by reviewers with write access.
To github.com:whitequark/parser.git
 ! [remote rejected] master -> master (protected branch hook declined)

However I see an "Edit" icon on the top right corner of Readme. Weird. Could you push it yourself please?

[whitequark]

@iliabylich I removed branch protection. I trust you wouldn't screw things up. Other collaborators also seem fine and mostly inactive anyway.

[iliabylich]

These words make me nervous. Thanks and done, parser 2.6.2.0 has been released.

[whitequark]

@iliabylich I'd add you to repo owners (which lets you bypass protection with one additional click) but it looks like GitHub only has that feature for organizations now.

[Drenmi]

Thanks, @whitequark and @iliabylich. 🙇