Using ubuntu-latest might result in incompatibilities when this image
changes to a different version of Ubuntu. For example, the Ubuntu 24.04
image no longer includes imagemagick, meaning that we'll have to install
it manually when using Ubuntu 24.04.
The main reason for this change is that Pronto doesn't run in pull
requests opened by external contributors, and we haven't found how to
fix this issue.
Another reason is that Pronto only detects issues in the lines where the
changes are done, but sometimes we introduce issues related to other
lines and those aren't detected by Pronto. Also, when adding or changing
Rubocop rules, or when we update Rubocop, Pronto doesn't check whether
those rules are applied in every Ruby and ERB file, and we sometimes
forget to do so (particularly in ERB files).
So, from now, the linters will check all the code in every pull request.
Note we're now excluding the `vendor` folder in our linters because the
`setup-ruby` action actions generates a `vendor/bundle/` folder with all
our gem dependencies, and we don't want to check those files.
We had the `*` because, in the past, pull request could be opened by
either dependabot or dependabot-bot. That's no longer the case since we
started using dependabot v2.
