Add Ruby3 preview1 to build matrix with allow_failures

[benoittgt]

Hello

https://www.ruby-lang.org/en/news/2020/09/25/ruby-3-0-0-preview1-released/
I choose to be very explicit. rvm use 3.0.0-preview1 was not working, rvm use 3 yes but I think we should be explicit when we speak about version. :)

Have a nice evening

[JonRowe]

Beat me to it! I'd like to get this out of allow-failures as soon as possible, but that might be a job for RSpec 4.

[JonRowe]

Do you want to run the PR generator?

[benoittgt]

Beat me to it! I'd like to get this out of allow-failures as soon as possible, but that might be a job for RSpec 4.

I would love too! 😄

[benoittgt]

Ok I failed and run the command for plain text files too. That explain the amount of closed pull request.

I pushed two change directly on master that where not committed here.

• diff-lcs change d97105d
• and main branch definition on travis file b522283