Add Ruby 3.2 to test matrix

[mataku]

Description

add Ruby 3.2 to GitHub Actions test matrix and fix failed specs to ensure that Danger works with Ruby 3.2 on CI

it seems #1411 has been reverted, this is a restore of it

Changes

On Ruby 3.2, some tests using WebMock fail like the one below.

Result of a test case using WebMock

$ bundle rspec spec/lib/danger/request_sources/gitlab_spec.rb:147
Run options: include {:locations=>{"./spec/lib/danger/request_sources/gitlab_spec.rb"=>[147]}}

Randomized with seed 60974

Danger::RequestSources::GitLab
  valid server response
    set its mr_json (FAILED - 1)

Failures:

  1) Danger::RequestSources::GitLab valid server response set its mr_json
     Failure/Error: WebMock.stub_request(:get, url).with(headers: expected_headers).to_return(raw_file)

     TypeError:
       no implicit conversion from nil to integer
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/response.rb:124:in `read_raw_response'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/response.rb:18:in `initialize'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/response.rb:10:in `new'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/response.rb:10:in `response_for'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/request_stub.rb:21:in `block in to_return'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/request_stub.rb:21:in `map'
     # ./vendor/bundle/ruby/3.2.0/gems/webmock-3.5.0/lib/webmock/request_stub.rb:21:in `to_return'
     # ./spec/support/gitlab_helper.rb:50:in `stub_merge_request'
     # ./spec/lib/danger/request_sources/gitlab_spec.rb:109:in `block (3 levels) in <top (required)>'

Finished in 0.01012 seconds (files took 0.32573 seconds to load)
1 example, 1 failure

it seems net-protocol (v0.2.1) bundled gem in Ruby 3.2 and the version of WebMock currently used in Danger seem to be incompatible. Ruby 3.1.1 uses net-protocol 0.1.2, so you will see that tests pass if fix net-protocol to it.

However, changing the version of the bundled gem is a bit hard to manage, so update WebMock so that the test passes

[mataku]

I will fix that something is broken with Ruby 3.1 on Windows
https://github.com/danger/danger/actions/runs/4659124031/jobs/8245637996?pr=1434

---

Tests fail for some reason when version 3.18 or higher of WebMock is used, so just fixed it to 3.16.X

[orta]

Ace, thaniks 👍🏻